equality. Thus, domestic violence and abuse are rationalized.
- Understanding between husband and wife:
The way in which a couple understands each other affects domestic violence. When a couple does not understand each other, it will cause conflict and violence [71].
- Another cause of domestic violence and re-incidence of domestic violence is the suffering of women when domestic violence occurs. The reasons are:
- Low self-esteem:
Abused women not only have low self-esteem but also lack the capacity to be beaten and injured. Furthermore, they tend to prioritize the needs of others over their own.
- Unrealistic hope:
A woman who is beaten still loves and is loyal to her husband. She endures it all and hopes that her husband will change and become a good person. After each promise and apology from her husband, the wife always has hope and believes it.
- Isolation:
One characteristic of battered women is that they gradually become socially isolated, avoiding seeing friends and relatives because their husbands expect them to stay at home. Sometimes women isolate themselves because they fear that their friends and family will find out about the abuse and that their husbands will be angry if they find out.
- Based on economics and emotions:
The abused wife is very dependent on her husband. She has no experience and has never had help from anyone before. She has always relied on her husband financially and cannot think of any other way.
- Traditional concept of marriage:
Most women have the traditional concept of raising children and obeying their husbands, so when their married life is not good, they always endure it alone and think that is their mission.
2.1.1.2. Causes and conditions within the school
The cause of violent behavior is due to learning (imitation):
Violent behavior is observed and imitated by others. They see that those behaviors are not punished, not considered criminal, so they imitate, and are completely unaware that those behaviors are criminal. Therefore, from the time they are children with direct or indirect experience of being abused until adulthood, the possibility of abusing their wives and children is high, so violent behavior is highly hereditary through generations. [74].
Within the school, if children are subjected to school violence or commit school violence, when they grow up and get married, they are likely to commit domestic violence or become victims of domestic violence.
2.1.1.3. Causes and conditions from the social scope
- Sense of ownership:
Korean society has the idea that men earn money and support their families. Women only raise children and focus on housework, so women have no economic power. Men always have authority and confidence in their ability to support their wives and children.
Family relationships are not equal, like the superior-subordinate relationship, the master-slave relationship. Therefore, beating and mistreatment are rationalized. According to a policy survey by the Korean Criminal Policy Research Institute in 1999, which surveyed both men and women, 54% of men believed that it was okay to beat their wives, and 46% of women believed that it was okay for men to beat their wives. Society still has this kind of awareness, so it spreads and permeates deeply into families of all ages.
- Social evils:
Social evils exist in every society. And social evils such as: alcohol, gambling, drug addiction, prostitution are direct causes leading to domestic violence. Social evils make people lose their reason, lose their humanity, affect the economy and happiness of families. Social evils give rise to domestic violence.
- Cultural awareness and regulations that cause a culture of violence:
Korea has a very common culture that when there are problems and conflicts, violence is used to solve them. In the media, on TV, and in movies, violent men are portrayed as heroic and good (aestheticized), so young people are influenced. When there are problems, they only use force to solve them.
- Wrong social perception of family issues:
This perception holds that family problems are each family's private problems and that others should not interfere. Society also does not want to interfere with each family's private problems. In the family, the father is the head of the family and has the right to use violence against his wife and children.
In family relationships, there is no respect for personality and trust. The person who is abused does not have self-confidence and does not adapt to society. That person is also greatly affected and changes to be violent.
- Indifferent attitude of public authorities:
The prosecutor believes that domestic violence is a problem between husband and wife, so family problems should be solved within the family. Not realizing that it is a crime, the problem of domestic violence is taken lightly. [81]
2.1.2. Subjective causes and conditions belong to the offender
2.1.2.1. Psychology of criminals
-Mental reasoning (Poor personality, mental illness):
Domestic violence is caused by the personality of the perpetrator or mental illness. According to research by psychiatrists, those who commit domestic violence always want to repeat the act of violence, and the next acts of violence are always at a higher level than the previous ones. The psychology of the perpetrator will stabilize after committing the act of violence. This process is a continuous process. The perpetrator is not a mental patient, but those people have an unstable and excessively dissatisfied personality, conservatism, anti-social personality and abnormal personality.
- Social learning theory (Experienced domestic violence as a child):
From childhood to adulthood, the perpetrator has had experience with domestic violence and has witnessed domestic violence. Domestic violence also forms habits between the victim and the perpetrator.
Individual learning as it is is like a blank sheet of paper, which through observation of simulation of violent activity leads to the occurrence of violent behavior. When the perpetrator
If they use violence to express anger, we know what methods their parents used to carry out their violent acts.
Violence is learned, so the family is like a training ground for violence. When children have witnessed domestic violence, seeing their father beat their mother, later that person is very likely to beat his wife.
- Perceptual action theory (Misunderstanding about communication and exchange methods):
The perpetrator thinks that domestic violence is the most effective way to communicate. In a relationship between husband and wife, just talking is not enough to understand each other. To resolve conflicts in the family, to help husband and wife understand each other better, violence must be used.
- Feminism theory (Patriarchal concept, considering women inferior):
According to patriarchal consciousness, patriarchal concept, men use authority to control women. Women are ruled and monitored is a policy that has been legalized throughout history. Patriarchal social system is not equal, mistreats wives and underestimates women.
- Stress theory (People under a lot of stress are more likely to commit violent acts)
force):
Because of stress, we use violence. When there is stress in life and work
The husband uses violence against his wife to relieve stress. When the mind is at its peak, using hands and feet will relieve stress and stabilize the mind. That is why people who commit violence when stressed always beat their wives. [71].
According to a study by the Institute of Social Welfare Research - Yeonse University (1999), highly stressed men beat their wives (45.6%), while less stressed men beat their wives only 18.6%.
2.1.2.2. Personal factors:
- Anger plays a decisive role in domestic violence:
Hot-tempered people often prefer to solve problems with violence. Perhaps they were abused as children and were not equipped with the necessary life skills to control violent behavior. When they are too angry, they express their power by using violence.
fist. When a hot-tempered husband argues with his wife, he chooses violence to solve the problem rather than words. When a patriarchal husband argues with his wife, his first reaction is to refute what his wife says with violence. [55].
- Lack of ability to regulate anger:
As children, these people experienced violence and abuse.
When he grew up, he used violence against his wife.
- Lack of ability to express:
Forming patriarchal cultural conditions, violent men when feeling insecure and afraid sometimes express it with love, sometimes express it with violence.
- Based on feelings:
Most men who abuse their wives are very intimate, but when they have to rely on their wives, they feel very angry. Worse is the disease of doubting their wives.
- Decreased self-esteem:
Men who abuse their wives often become depressed and have low self-esteem.
- Addiction to alcohol and drugs:
According to some reports, perpetrators of violence often use alcohol and drugs. 67% of perpetrators of violence drink alcohol.
- False beliefs and religions:
Abusive husbands often think that women are inferior to men, want their wives to obey them, and do not allow them to speak or have opinions. Men think that God created men superior to women, so men have the right to hit women.
- Social isolation or economic problems:
Social isolation or economic isolation is a cause of violence between spouses. Job dissatisfaction and economic stress are also causes of insecurity and anger in men. Therefore, they often beat their wives.
The above are the causes and conditions of domestic violence in Korea, drawn from reality and from the research theories of experts. Below are some statistics on the causes of domestic violence in Korea.
Table 2.1. Statistics on the occurrence of domestic violence (Reasons why women are beaten)
Reasons why women are beaten
Number | Ratio (%) | |
When there is a problem with the child | 16 | 5.6 |
When requesting living expenses | 13 | 4.5 |
When talking about the husband's affair | 24 | 8.4 |
When husband drinks alcohol | 72 | 25.2 |
When wife argues back | 67 | 23.4 |
When not meeting husband's sexual needs | 14 | 5.0 |
According to husband's feelings | 63 | 22.0 |
Other reasons | 17 | 5.9 |
Total | 286 | 100 |
Maybe you are interested!
-
Raising Income Levels to Create Favorable Conditions for the Teaching Staff to Work with Peace of Mind, Promoting Their Subjective Factors in Officer Training -
Car body electrical practice - 8
zt2i3t4l5ee
zt2a3gs
zt2a3ge
zc2o3n4t5e6n7ts
If the voltage is out of specification, replace the wire or connector.
If the voltage is within specification, install the front fog light relay and follow step 5.
Step 5 Check the front fog light switch
- Remove the D4 connector of the fog light switch
- Use a multimeter to measure the resistance of the front fog light switch.
Measurement location
Condition
Standard
D4-3 (BFG) -D4-4 (LFG)
Light switchFront Fog OFF
>10kΩ
D4-3 (BFG) -D4-4 (LFG)
Front fog light switchON
<1 Ω
- Standard resistor
D4 connector is located on the combination switch assembly.
If the resistance is out of specification, replace the combination switch (the fog light switch is located in the combination switch).
If the resistance is within specification, follow step 6.
Step 6 Check wiring and connectors (front fog light relay-light selector switch)
- Disconnect connector D4 of the combination switch assembly
- Use a voltmeter to measure the voltage value of jack D4 on the wire side.
Measurement location
Control modecontrol
Standard
D4-3 (BFG) - (-) AQ
TAIL
11 to 14 V
D4 connector for the wiring of the combination switch assembly
If the voltage does not meet the standard, replace the wire or connector.
If the voltage is within standard, there may have been an error in the previous measurements.
Step 7 Check the front fog lights
- Remove the front fog light electrical connector.
- Supply battery voltage to the fog lamp terminals
Jack 8, B9 of front fog lamp on the electrical side
blind first.
Power supply location
Terms and Conditions
Battery positive terminal - Terminal 2Battery negative terminal - Terminal 1
Fog lightsbefore morning
- If the light does not come on, replace the bulb.
If the light is on, re-plug the jack and continue to step 8.
Step 8 Check wiring and connectors (relay and front fog lights)
- Disconnect the B8 and B9 connectors of the front fog lights.
- Use a voltmeter to measure voltage at the following locations:
Measurement location
Switch location
Terms and Conditions
B8-2 - (-) AQ
Electric lock ON TAIL size switchFog switch ON
11 to 14 V
B9-2 - (-) AQ
Electric lock ONTAIL size switch Fog switch ON
11 to 14 V
B8 and B9 connectors on the front fog lamp wiring side
Voltage is not up to standard, repair or replace the jack. If up to standard, there may have been an error in the measurement process.
2.2.4. Procedure for removing, installing and adjusting fog lights 1. Procedure for removing
- Remove the front inner ear pads
Use a screwdriver to remove the 3 screws and remove the front part of the front inner ear liner
-Remove the fog light assembly
+ Disconnect the connector.
+ Use a screwdriver to remove 3 screws to remove the fog light cover
2. Installation sequence
-Rotate the fog lamp bulb in the direction indicated by the arrow as shown in the figure and remove the fog lamp from the fog lamp assembly.
-Rotate the fog light bulb in the direction indicated by the arrow as shown in the figure and install the light into the fog light assembly.
- Use a screwdriver to install the fog light cover
-Install the electrical connector
Attention: Be careful not to damage the plastic thread on the lamp assembly.
- Install the front inner ear pads
Use a screwdriver to install the front inner bumper with 3 screws.
3. Prepare the vehicle to adjust the fog light convergence. Prepare the vehicle:
- Make sure there is no damage or deformation to the vehicle body around the fog lights.
- Add fuel to the fuel tank
- Add oil to standard level.
- Add engine coolant to standard level.
- Inflate the tire to standard pressure.
- Place spare tire, tools and jack in original design position
- Do not leave any load in the luggage compartment.
- Let a person weighing about 75 kg sit in the driver's seat.
4. Prepare to check the fog light convergence
a/ Prepare the vehicle status as follows:
- Place the car in a dark enough place to see the lines. The lines are the dividing line, below which the light from the fog lights can be seen but above which it cannot.
- Place the car perpendicular to the wall.
- Keep a distance of 7.62 m between the center of the fog lamp and the wall.
- Park the car on level ground.
- Press the car down a few times to stabilize the suspension.
Note: A distance of approximately 7.62 m is required between the vehicle (fog lamp center) and the wall to adjust the convergence correctly. If the distance of 7.62 m cannot be achieved, set the correct distance of 3 m to check and adjust the fog lamp convergence. (Since the target area varies with the distance, please follow the instructions as shown in the figure.)
b/ Prepare a piece of thick white paper about 2 m high and 4 m wide to use as a screen.
c/ Draw a vertical line through the center of the screen (line V).
d/ Set the screen as shown in the picture. Note:
- Keep the screen perpendicular to the ground.
- Align the V line on the screen with the center of the vehicle.
e/Draw the reference lines (H, V LH and V RH lines) on the screen as shown in the figure.HINT:
Mark the center of the fog lamp on the screen. If the center mark cannot be seen on the fog lamp, use the center of the fog lamp or the manufacturer's name mark on the fog lamp as the center mark.
H line (fog light height):
Draw a line across the screen so that it passes through the center mark. Line H should be at the same height as the center mark of the fog light bulb.
Line V LH, V RH (center mark position of left fog lamp LH and right fog lamp RH):
Draw two lines so that they intersect line H at the center marks.
5. Check the fog light convergence
a/ Cover the fog lamp or remove the connector of the other side fog lamp to prevent light from the unchecked fog lamp from affecting the fog lamp convergence test.
b/ Start the engine.
c/ Turn on the fog lights and make sure that the dividing line is outside the standard area as shown in the drawing.
6. Adjust the fog light convergence
Use a screwdriver to adjust the fog light to the standard area by turning the toe adjustment screw.
Note: If the screw is adjusted too far, loosen it and then tighten it again, so that the last rotation of the light adjustment screw is clockwise.
3. Self-study questions
1. Describe the operating principle of the lighting system with automatic headlight function
2. Describe the operating principle of the lighting system with the function of rotating headlights when turning
3. Draw diagram and connect lighting system on Hyundai Porter car
4. Draw diagram and connect lighting system on Honda Accord 1992
5. Draw the lighting circuit on a 1993 Toyota Lexus
LESSON 3 MAINTENANCE AND REPAIR OF SIGNAL SYSTEM
I. IMPLEMENTATION GOAL
After completing this lesson, students will be able to:
- Distinguish between types of signals on cars
- Correctly describe common symptoms and suspected areas causing damage.
- Connecting signal circuits ensures technical requirements
- Disassemble, install, check, maintain and repair the signal system to ensure technical requirements.
- Ensure safety in work and industrial hygiene
II. LESSON CONTENT
1. General description
The signal system equipped on cars aims to create signals to notify other vehicles participating in traffic about the vehicle's operating status such as: stopping, parking, braking, reversing, turning...
Signals are used either by light such as headlamps, brake lights, turn signals….. or by sound such as horns, reverse music….
Just like the lighting system. A signal system circuit usually consists of: battery, fuse, wire, relay, electrical load and control switch. Only some switches of the signal system are on the combination switch. The switches of other signals are usually located in different locations such as in the gearbox or brake pedal……
2. Maintenance and repair
2.1. Turn signals and hazard lights
The installation location of the turn signal is shown in Figure 3.1. The turn signal control switch is located in the combination switch under the steering wheel. Turning this switch to the right or left will make the turn signal turn right or left.
The hazard light switch is used when the vehicle has a problem while participating in traffic. When the hazard light switch is turned on, all the turn signals on the vehicle will light up at a certain frequency. The hazard light switch is usually placed separately from the turn signal switch (some old cars integrate the hazard and turn signal switches on the same combination switch cluster).
Figure 3.1 Turn signal switch Figure 3.2 Hazard switch
The part that generates the flashing frequency for the lights is called a turn signal relay. The turn signal relay usually has 3 terminals: B (positive power supply); E (negative power supply); L (providing the turn signal switch to distribute to the
lamp)
2.1.1. Circuit diagram
To generate the frequency for the turn signal, a turn signal relay is used in the turn signal circuit. The current from the turn signal relay will be sent to the turn signal switch assembly to distribute the current to the turn signal lights for the driver's purpose.
Figure 3.3. Schematic diagram of a turn signal circuit without a hazard switch
1. Battery; 2. Electric lock; 3. Turn signal relay; 4. Turn signal switch; 5. Turn signal lamp; 6. Turn signal lamp; 7. Hazard switch
Figure 3.4 Schematic diagram of turn signal circuit with hazard switch
1. Battery; 2. Combination switch cluster; 3. Turn signal;
4. Turn signal light; 5. Turn signal relay
Today's cars no longer use three-pin turn signal relays (B, L, E) but use eight-pin turn signal relays (figure 3.5) (pin number 8 is used for hazard lights).
For this type, the current supplying the turn signal lights is supplied directly from the turn signal relay to the lights.
div.maincontent .p { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; } div.maincontent p { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; } div.maincontent .s1 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 13pt; } div.maincontent .s2 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s3 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s4 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 13pt; } div.maincontent .s5 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 13pt; vertical-align: 1pt; } div.maincontent .s6 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 11pt; } div.maincontent .s7 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; vertical-align: -9pt; } div.maincontent .s8 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 11pt; } div.maincontent .s9 { color: #008000; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s10 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; te -
![Qos Assurance Methods for Multimedia Communications
zt2i3t4l5ee
zt2a3gs
zt2a3ge
zc2o3n4t5e6n7ts
low. The EF PHB requires a sufficiently large number of output ports to provide low delay, low loss, and low jitter.
EF PHBs can be implemented if the output ports bandwidth is sufficiently large, combined with small buffer sizes and other network resources dedicated to EF packets, to allow the routers service rate for EF packets on an output port to exceed the arrival rate λ of packets at that port.
This means that packets with PHB EF are considered with a pre-allocated amount of output bandwidth and a priority that ensures minimum loss, minimum delay and minimum jitter before being put into operation.
PHB EF is suitable for channel simulation, leased line simulation, and real-time services such as voice, video without compromising on high loss, delay and jitter values.
Figure 2.10 Example of EF installation
Figure 2.10 shows an example of an EF PHB implementation. This is a simple priority queue scheduling technique. At the edges of the DS domain, EF packet traffic is prioritized according to the values agreed upon by the SLA. The EF queue in the figure needs to output packets at a rate higher than the packet arrival rate λ. To provide an EF PHB over an end-to-end DS domain, bandwidth at the output ports of the core routers needs to be allocated in advance to ensure the requirement μ > λ. This can be done by a pre-configured provisioning process. In the figure, EF packets are placed in the priority queue (the upper queue). With such a length, the queue can operate with μ > λ.
Since EF was primarily used for real-time services such as voice and video, and since real-time services use UDP instead of TCP, RED is generally
not suitable for EF queues because applications using UDP will not respond to random packet drop and RED will strip unnecessary packets.
2.2.4.2 Assured Forwarding (AF) PHB
PHB AF is defined by RFC 2597. The purpose of PHB AF is to deliver packets reliably and therefore delay and jitter are considered less important than packet loss. PHB AF is suitable for non-real-time services such as applications using TCP. PHB AF first defines four classes: AF1, AF2, AF3, AF4. For each of these AF classes, packets are then classified into three subclasses with three distinct priority levels.
Table 2.8 shows the four AF classes and 12 AF subclasses and the DSCP values for the 12 AF subclasses defined by RFC 2597. RFC 2597 also allows for more than three separate priority levels to be added for internal use. However, these separate priority levels will only have internal significance.
PHB Class
PHB Subclass
Package type
DSCP
AF4
AF41
Short
100010
AF42
Medium
100100
AF43
High
100110
AF3
AF31
Short
011010
AF32
Medium
011100
AF33
High
011110
AF2
AF21
Short
010010
AF22
Medium
010100
AF23
High
010110
AF1
AF11
Short
001010
AF12
Medium
001100
AF13
High
001110
Table 2.8 AF DSCPs
The AF PHB ensures that packets are forwarded with a high probability of delivery to the destination within the bounds of the rate agreed upon in an SLA. If AF traffic at an ingress port exceeds the pre-priority rate, which is considered non-compliant or “out of profile”, the excess packets will not be delivered to the destination with the same probability as the packets belonging to the defined traffic or “in profile” packets. When there is network congestion, the out of profile packets are dropped before the in profile packets are dropped.
When service levels are defined using AF classes, different quantity and quality between AF classes can be realized by allocating different amounts of bandwidth and buffer space to the four AF classes. Unlike
EF, most AF traffic is non-real-time traffic using TCP, and the RED queue management strategy is an AQM (Adaptive Queue Management) strategy suitable for use in AF PHBs. The four AF PHB layers can be implemented as four separate queues. The output port bandwidth is divided into four AF queues. For each AF queue, packets are marked with three “colors” corresponding to three separate priority levels.
In addition to the 32 DSCP 1 groups defined in Table 2.8, 21 DSCPs have been standardized as follows: one for PHB EF, 12 for PHB AF, and 8 for CSCP. There are 11 DSCP 1 groups still available for other standards.
2.2.5.Example of Differentiated Services
We will look at an example of the Differentiated Service model and mechanism of operation. The architecture of Differentiated Service consists of two basic sets of functions:
Edge functions: include packet classification and traffic conditioning. At the inbound edge of the network, incoming packets are marked. In particular, the DS field in the packet header is set to a certain value. For example, in Figure 2.12, packets sent from H1 to H3 are marked at R1, while packets from H2 to H4 are marked at R2. The labels on the received packets identify the service class to which they belong. Different traffic classes receive different services in the core network. The RFC definition uses the term behavior aggregate rather than the term traffic class. After being marked, a packet can be forwarded immediately into the network, delayed for a period of time before being forwarded, or dropped. We will see that there are many factors that affect how a packet is marked, and whether it is forwarded immediately, delayed, or dropped.
Figure 2.12 DiffServ Example
Core functionality: When a DS-marked packet arrives at a Diffservcapable router, the packet is forwarded to the next router based on
Per-hop behavior is associated with packet classes. Per-hop behavior affects router buffers and the bandwidth shared between competing classes. An important principle of the Differentiated Service architecture is that a routers per-hop behavior is based only on the packets marking or the class to which it belongs. Therefore, if packets sent from H1 to H3 as shown in the figure receive the same marking as packets from H2 to H4, then the network routers treat the packets exactly the same, regardless of whether the packet originated from H1 or H2. For example, R3 does not distinguish between packets from h1 and H2 when forwarding packets to R4. Therefore, the Differentiated Service architecture avoids the need to maintain router state about separate source-destination pairs, which is important for network scalability.
Chapter Conclusion
Chapter 2 has presented and clarified two main models of deploying and installing quality of service in IP networks. While the traditional best-effort model has many disadvantages, later models such as IntServ and DiffServ have partly solved the problems that best-effort could not solve. IntServ follows the direction of ensuring quality of service for each separate flow, it is built similar to the circuit switching model with the use of the RSVP resource reservation protocol. IntSer is suitable for services that require fixed bandwidth that is not shared such as VoIP services, multicast TV services. However, IntSer has disadvantages such as using a lot of network resources, low scalability and lack of flexibility. DiffServ was born with the idea of solving the disadvantages of the IntServ model.
DiffServ follows the direction of ensuring quality based on the principle of hop-by-hop behavior based on the priority of marked packets. The policy for different types of traffic is decided by the administrator and can be changed according to reality, so it is very flexible. DiffServ makes better use of network resources, avoiding idle bandwidth and processing capacity on routers. In addition, the DifServ model can be deployed on many independent domains, so the ability to expand the network becomes easy.
Chapter 3: METHODS TO ENSURE QoS FOR MULTIMEDIA COMMUNICATIONS
In packet-switched networks, different packet flows often have to share the transmission medium all the way to the destination station. To ensure the fair and efficient allocation of bandwidth to flows, appropriate serving mechanisms are required at network nodes, especially at gateways or routers, where many different data flows often pass through. The scheduler is responsible for serving packets of the selected flow and deciding which packet will be served next. Here, a flow is understood as a set of packets belonging to the same priority class, or originating from the same source, or having the same source and destination addresses, etc.
In normal state when there is no congestion, packets will be sent as soon as they are delivered. In case of congestion, if QoS assurance methods are not applied, prolonged congestion can cause packet drops, affecting service quality. In some cases, congestion is prolonged and widespread in the network, which can easily lead to the network being frozen, or many packets being dropped, seriously affecting service quality.
Therefore, in this chapter, in sections 3.2 and 3.3, we introduce some typical network traffic load monitoring techniques to predict and prevent congestion before it occurs through the measure of dropping (removing) packets early when there are signs of impending congestion.
3.1. DropTail method
DropTail is a simple, traditional queue management method based on FIFO mechanism. All incoming packets are placed in the queue, when the queue is full, the later packets are dropped.
Due to its simplicity and ease of implementation, DropTail has been used for many years on Internet router systems. However, this algorithm has the following disadvantages:
− Cannot avoid the phenomenon of “Lock out”: Occurs when 1 or several traffic streams monopolize the queue, making packets of other connections unable to pass through the router. This phenomenon greatly affects reliable transmission protocols such as TCP. According to the anti-congestion algorithm, when locked out, the TCP connection stream will reduce the window size and reduce the packet transmission speed exponentially.
− Can cause Global Synchronization: This is the result of a severe “Lock out” phenomenon. Some neighboring routers have their queues monopolized by a number of connections, causing a series of other TCP connections to be unable to pass through and simultaneously reducing the transmission speed. After those monopolized connections are temporarily suspended,
Once the queue is cleared, it takes a considerable amount of time for TCP connections to return to their original speed.
− Full Queue phenomenon: Data transmitted on the Internet often has an explosion, packets arriving at the router are often in clusters rather than in turn. Therefore, the operating mechanism of DropTail makes the queue easily full for a long period of time, leading to the average delay time of large packets. To avoid this phenomenon, with DropTail, the only way is to increase the routers buffer, this method is very expensive and ineffective.
− No QoS guarantee: With the DropTail mechanism, there is no way to prioritize important packets to be transmitted through the router earlier when all are in the queue. Meanwhile, with multimedia communication, ensuring connection and stable speed is extremely important and the DropTail algorithm cannot satisfy.
The problem of choosing the buffer size of the routers in the network is to “absorb” short bursts of traffic without causing too much queuing delay. This is necessary in bursty data transmission. The queue size determines the size of the packet bursts (traffic spikes) that we want to be able to transmit without being dropped at the routers.
In IP-based application networks, packet dropping is an important mechanism for indirectly reporting congestion to end stations. A solution that prevents router queues from filling up while reducing the packet drop rate is called dynamic queue management.
3.2. Random elimination method – RED
3.2.1 Overview
RED (Random Early Detection of congestion; Random Early Drop) is one of the first AQM algorithms proposed in 1993 by Sally Floyd and Van Jacobson, two scientists at the Lawrence Berkeley Laboratory of the University of California, USA. Due to its outstanding advantages compared to previous queue management algorithms, RED has been widely installed and deployed on the Internet.
The most fundamental point of their work is that the most effective place to detect congestion and react to it is at the gateway or router.
Source entities (senders) can also do this by estimating end-to-end delay, throughput variability, or the rate of packet retransmissions due to drop. However, the sender and receiver view of a particular connection cannot tell which gateways on the network are congested, and cannot distinguish between propagation delay and queuing delay. Only the gateway has a true view of the state of the queue, the link share of the connections passing through it at any given time, and the quality of service requirements of the
traffic flows. The RED gateway monitors the average queue length, which detects early signs of impending congestion (average queue length exceeding a predetermined threshold) and reacts appropriately in one of two ways:
− Drop incoming packets with a certain probability, to indirectly inform the source of congestion, the source needs to reduce the transmission rate to keep the queue from filling up, maintaining the ability to absorb incoming traffic spikes.
− Mark “congestion” with a certain probability in the ECN field in the header of TCP packets to notify the source (the receiving entity will copy this bit into the acknowledgement packet).
Figure 3. 1 RED algorithm
The main goal of RED is to avoid congestion by keeping the average queue size within a sufficiently small and stable region, which also means keeping the queuing delay sufficiently small and stable. Achieving this goal also helps: avoid global synchronization, not resist bursty traffic flows (i.e. flows with low average throughput but high volatility), and maintain an upper bound on the average queue size even in the absence of cooperation from transport layer protocols.
To achieve the above goals, RED gateways must do the following:
− The first is to detect congestion early and react appropriately to keep the average queue size small enough to keep the network operating in the low latency, high throughput region, while still allowing the queue size to fluctuate within a certain range to absorb short-term fluctuations. As discussed above, the gateway is the most appropriate place to detect congestion and is also the most appropriate place to decide which specific connection to report congestion to.
− The second thing is to notify the source of congestion. This is done by marking and notifying the source to reduce traffic. Normally the RED gateway will randomly drop packets. However, if congestion
If congestion is detected before the queue is full, it should be combined with packet marking to signal congestion. The RED gateway has two options: drop or mark; where marking is done by marking the ECN field of the packet with a certain probability, to signal the source to reduce the traffic entering the network.
− An important goal that RED gateways need to achieve is to avoid global synchronization and not to resist traffic flows that have a sudden characteristic. Global synchronization occurs when all connections simultaneously reduce their transmission window size, leading to a severe drop in throughput at the same time. On the other hand, Drop Tail or Random Drop strategies are very sensitive to sudden flows; that is, the gateway queue will often overflow when packets from these flows arrive. To avoid these two phenomena, gateways can use special algorithms to detect congestion and decide which connections will be notified of congestion at the gateway. The RED gateway randomly selects incoming packets to mark; with this method, the probability of marking a packet from a particular connection is proportional to the connections shared bandwidth at the gateway.
− Another goal is to control the average queue size even without cooperation from the source entities. This can be done by dropping packets when the average size exceeds an upper threshold (instead of marking it). This approach is necessary in cases where most connections have transmission times that are less than the round-trip time, or where the source entities are not able to reduce traffic in response to marking or dropping packets (such as UDP flows).
3.2.2 Algorithm
This section describes the algorithm for RED gateways. RED gateways calculate the average queue size using a low-pass filter. This average queue size is compared with two thresholds: minth and maxth. When the average queue size is less than the lower threshold, no incoming packets are marked or dropped; when the average queue size is greater than the upper threshold, all incoming packets are dropped. When the average queue size is between minth and maxth, each incoming packet is marked or dropped with a probability pa, where pa is a function of the average queue size avg; the probability of marking or dropping a packet for a particular connection is proportional to the bandwidth share of that connection at the gateway. The general algorithm for a RED gateway is described as follows: [5]
For each packet arrival
Caculate the average queue size avg If minth ≤ avg < maxth
div.maincontent .s1 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 15pt; }
div.maincontent .s2 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 15pt; }
div.maincontent .p { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; }
div.maincontent p { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; }
div.maincontent .s3 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 14pt; }
div.maincontent .s4 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; }
div.maincontent .s5 { color: black; font-family:Times New Roman, serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; }
div.maincontent .s6 { color: black; font-family:Times New Roman, serif; font-style: italic; font-weight: bold; text-decoration: none; font-size: 14pt; }
div.maincontent .s7 { color: black; font-family:Wingdings; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; }
div.maincontent .s8 { color: black; font-family:Arial, sans-serif; font-style: italic; font-weight: bold; text-decoration: none; font-size: 15pt; }
div.maincontent .s9 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 14pt; }
div.maincontent .s10 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 9pt; vertical-align: 6pt; }
div.maincontent .s11 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 13pt; }
div.maincontent .s12 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 10pt; }
div.maincontent .s13 { color: black; font-family:Times New Roman, serif; font-style: normal; font-weight: normal; text-d](https://tailieuthamkhao.com/uploads/2022/05/15/danh-gia-hieu-qua-dam-bao-qos-cho-truyen-thong-da-phuong-tien-cua-chien-6-1-120x90.jpg)
Qos Assurance Methods for Multimedia Communications
zt2i3t4l5ee
zt2a3gs
zt2a3ge
zc2o3n4t5e6n7ts
low. The EF PHB requires a sufficiently large number of output ports to provide low delay, low loss, and low jitter.
EF PHBs can be implemented if the output port's bandwidth is sufficiently large, combined with small buffer sizes and other network resources dedicated to EF packets, to allow the router's service rate for EF packets on an output port to exceed the arrival rate λ of packets at that port.
This means that packets with PHB EF are considered with a pre-allocated amount of output bandwidth and a priority that ensures minimum loss, minimum delay and minimum jitter before being put into operation.
PHB EF is suitable for channel simulation, leased line simulation, and real-time services such as voice, video without compromising on high loss, delay and jitter values.
Figure 2.10 Example of EF installation
Figure 2.10 shows an example of an EF PHB implementation. This is a simple priority queue scheduling technique. At the edges of the DS domain, EF packet traffic is prioritized according to the values agreed upon by the SLA. The EF queue in the figure needs to output packets at a rate higher than the packet arrival rate λ. To provide an EF PHB over an end-to-end DS domain, bandwidth at the output ports of the core routers needs to be allocated in advance to ensure the requirement μ > λ. This can be done by a pre-configured provisioning process. In the figure, EF packets are placed in the priority queue (the upper queue). With such a length, the queue can operate with μ > λ.
Since EF was primarily used for real-time services such as voice and video, and since real-time services use UDP instead of TCP, RED is generally
not suitable for EF queues because applications using UDP will not respond to random packet drop and RED will strip unnecessary packets.
2.2.4.2 Assured Forwarding (AF) PHB
PHB AF is defined by RFC 2597. The purpose of PHB AF is to deliver packets reliably and therefore delay and jitter are considered less important than packet loss. PHB AF is suitable for non-real-time services such as applications using TCP. PHB AF first defines four classes: AF1, AF2, AF3, AF4. For each of these AF classes, packets are then classified into three subclasses with three distinct priority levels.
Table 2.8 shows the four AF classes and 12 AF subclasses and the DSCP values for the 12 AF subclasses defined by RFC 2597. RFC 2597 also allows for more than three separate priority levels to be added for internal use. However, these separate priority levels will only have internal significance.
PHB Class
PHB Subclass
Package type
DSCP
AF4
AF41
Short
100010
AF42
Medium
100100
AF43
High
100110
AF3
AF31
Short
011010
AF32
Medium
011100
AF33
High
011110
AF2
AF21
Short
010010
AF22
Medium
010100
AF23
High
010110
AF1
AF11
Short
001010
AF12
Medium
001100
AF13
High
001110
Table 2.8 AF DSCPs
The AF PHB ensures that packets are forwarded with a high probability of delivery to the destination within the bounds of the rate agreed upon in an SLA. If AF traffic at an ingress port exceeds the pre-priority rate, which is considered non-compliant or “out of profile”, the excess packets will not be delivered to the destination with the same probability as the packets belonging to the defined traffic or “in profile” packets. When there is network congestion, the out of profile packets are dropped before the in profile packets are dropped.
When service levels are defined using AF classes, different quantity and quality between AF classes can be realized by allocating different amounts of bandwidth and buffer space to the four AF classes. Unlike
EF, most AF traffic is non-real-time traffic using TCP, and the RED queue management strategy is an AQM (Adaptive Queue Management) strategy suitable for use in AF PHBs. The four AF PHB layers can be implemented as four separate queues. The output port bandwidth is divided into four AF queues. For each AF queue, packets are marked with three “colors” corresponding to three separate priority levels.
In addition to the 32 DSCP 1 groups defined in Table 2.8, 21 DSCPs have been standardized as follows: one for PHB EF, 12 for PHB AF, and 8 for CSCP. There are 11 DSCP 1 groups still available for other standards.
2.2.5.Example of Differentiated Services
We will look at an example of the Differentiated Service model and mechanism of operation. The architecture of Differentiated Service consists of two basic sets of functions:
Edge functions: include packet classification and traffic conditioning. At the inbound edge of the network, incoming packets are marked. In particular, the DS field in the packet header is set to a certain value. For example, in Figure 2.12, packets sent from H1 to H3 are marked at R1, while packets from H2 to H4 are marked at R2. The labels on the received packets identify the service class to which they belong. Different traffic classes receive different services in the core network. The RFC definition uses the term behavior aggregate rather than the term traffic class. After being marked, a packet can be forwarded immediately into the network, delayed for a period of time before being forwarded, or dropped. We will see that there are many factors that affect how a packet is marked, and whether it is forwarded immediately, delayed, or dropped.
Figure 2.12 DiffServ Example
Core functionality: When a DS-marked packet arrives at a Diffservcapable router, the packet is forwarded to the next router based on
Per-hop behavior is associated with packet classes. Per-hop behavior affects router buffers and the bandwidth shared between competing classes. An important principle of the Differentiated Service architecture is that a router's per-hop behavior is based only on the packet's marking or the class to which it belongs. Therefore, if packets sent from H1 to H3 as shown in the figure receive the same marking as packets from H2 to H4, then the network routers treat the packets exactly the same, regardless of whether the packet originated from H1 or H2. For example, R3 does not distinguish between packets from h1 and H2 when forwarding packets to R4. Therefore, the Differentiated Service architecture avoids the need to maintain router state about separate source-destination pairs, which is important for network scalability.
Chapter Conclusion
Chapter 2 has presented and clarified two main models of deploying and installing quality of service in IP networks. While the traditional best-effort model has many disadvantages, later models such as IntServ and DiffServ have partly solved the problems that best-effort could not solve. IntServ follows the direction of ensuring quality of service for each separate flow, it is built similar to the circuit switching model with the use of the RSVP resource reservation protocol. IntSer is suitable for services that require fixed bandwidth that is not shared such as VoIP services, multicast TV services. However, IntSer has disadvantages such as using a lot of network resources, low scalability and lack of flexibility. DiffServ was born with the idea of solving the disadvantages of the IntServ model.
DiffServ follows the direction of ensuring quality based on the principle of hop-by-hop behavior based on the priority of marked packets. The policy for different types of traffic is decided by the administrator and can be changed according to reality, so it is very flexible. DiffServ makes better use of network resources, avoiding idle bandwidth and processing capacity on routers. In addition, the DifServ model can be deployed on many independent domains, so the ability to expand the network becomes easy.
Chapter 3: METHODS TO ENSURE QoS FOR MULTIMEDIA COMMUNICATIONS
In packet-switched networks, different packet flows often have to share the transmission medium all the way to the destination station. To ensure the fair and efficient allocation of bandwidth to flows, appropriate serving mechanisms are required at network nodes, especially at gateways or routers, where many different data flows often pass through. The scheduler is responsible for serving packets of the selected flow and deciding which packet will be served next. Here, a flow is understood as a set of packets belonging to the same priority class, or originating from the same source, or having the same source and destination addresses, etc.
In normal state when there is no congestion, packets will be sent as soon as they are delivered. In case of congestion, if QoS assurance methods are not applied, prolonged congestion can cause packet drops, affecting service quality. In some cases, congestion is prolonged and widespread in the network, which can easily lead to the network being "frozen", or many packets being dropped, seriously affecting service quality.
Therefore, in this chapter, in sections 3.2 and 3.3, we introduce some typical network traffic load monitoring techniques to predict and prevent congestion before it occurs through the measure of dropping (removing) packets early when there are signs of impending congestion.
3.1. DropTail method
DropTail is a simple, traditional queue management method based on FIFO mechanism. All incoming packets are placed in the queue, when the queue is full, the later packets are dropped.
Due to its simplicity and ease of implementation, DropTail has been used for many years on Internet router systems. However, this algorithm has the following disadvantages:
− Cannot avoid the phenomenon of “Lock out”: Occurs when 1 or several traffic streams monopolize the queue, making packets of other connections unable to pass through the router. This phenomenon greatly affects reliable transmission protocols such as TCP. According to the anti-congestion algorithm, when locked out, the TCP connection stream will reduce the window size and reduce the packet transmission speed exponentially.
− Can cause Global Synchronization: This is the result of a severe “Lock out” phenomenon. Some neighboring routers have their queues monopolized by a number of connections, causing a series of other TCP connections to be unable to pass through and simultaneously reducing the transmission speed. After those monopolized connections are temporarily suspended,
Once the queue is cleared, it takes a considerable amount of time for TCP connections to return to their original speed.
− Full Queue phenomenon: Data transmitted on the Internet often has an explosion, packets arriving at the router are often in clusters rather than in turn. Therefore, the operating mechanism of DropTail makes the queue easily full for a long period of time, leading to the average delay time of large packets. To avoid this phenomenon, with DropTail, the only way is to increase the router's buffer, this method is very expensive and ineffective.
− No QoS guarantee: With the DropTail mechanism, there is no way to prioritize important packets to be transmitted through the router earlier when all are in the queue. Meanwhile, with multimedia communication, ensuring connection and stable speed is extremely important and the DropTail algorithm cannot satisfy.
The problem of choosing the buffer size of the routers in the network is to “absorb” short bursts of traffic without causing too much queuing delay. This is necessary in bursty data transmission. The queue size determines the size of the packet bursts (traffic spikes) that we want to be able to transmit without being dropped at the routers.
In IP-based application networks, packet dropping is an important mechanism for indirectly reporting congestion to end stations. A solution that prevents router queues from filling up while reducing the packet drop rate is called dynamic queue management.
3.2. Random elimination method – RED
3.2.1 Overview
RED (Random Early Detection of congestion; Random Early Drop) is one of the first AQM algorithms proposed in 1993 by Sally Floyd and Van Jacobson, two scientists at the Lawrence Berkeley Laboratory of the University of California, USA. Due to its outstanding advantages compared to previous queue management algorithms, RED has been widely installed and deployed on the Internet.
The most fundamental point of their work is that the most effective place to detect congestion and react to it is at the gateway or router.
Source entities (senders) can also do this by estimating end-to-end delay, throughput variability, or the rate of packet retransmissions due to drop. However, the sender and receiver view of a particular connection cannot tell which gateways on the network are congested, and cannot distinguish between propagation delay and queuing delay. Only the gateway has a true view of the state of the queue, the link share of the connections passing through it at any given time, and the quality of service requirements of the
traffic flows. The RED gateway monitors the average queue length, which detects early signs of impending congestion (average queue length exceeding a predetermined threshold) and reacts appropriately in one of two ways:
− Drop incoming packets with a certain probability, to indirectly inform the source of congestion, the source needs to reduce the transmission rate to keep the queue from filling up, maintaining the ability to absorb incoming traffic spikes.
− Mark “congestion” with a certain probability in the ECN field in the header of TCP packets to notify the source (the receiving entity will copy this bit into the acknowledgement packet).
Figure 3. 1 RED algorithm
The main goal of RED is to avoid congestion by keeping the average queue size within a sufficiently small and stable region, which also means keeping the queuing delay sufficiently small and stable. Achieving this goal also helps: avoid global synchronization, not resist bursty traffic flows (i.e. flows with low average throughput but high volatility), and maintain an upper bound on the average queue size even in the absence of cooperation from transport layer protocols.
To achieve the above goals, RED gateways must do the following:
− The first is to detect congestion early and react appropriately to keep the average queue size small enough to keep the network operating in the low latency, high throughput region, while still allowing the queue size to fluctuate within a certain range to absorb short-term fluctuations. As discussed above, the gateway is the most appropriate place to detect congestion and is also the most appropriate place to decide which specific connection to report congestion to.
− The second thing is to notify the source of congestion. This is done by marking and notifying the source to reduce traffic. Normally the RED gateway will randomly drop packets. However, if congestion
If congestion is detected before the queue is full, it should be combined with packet marking to signal congestion. The RED gateway has two options: drop or mark; where marking is done by marking the ECN field of the packet with a certain probability, to signal the source to reduce the traffic entering the network.
− An important goal that RED gateways need to achieve is to avoid global synchronization and not to resist traffic flows that have a sudden characteristic. Global synchronization occurs when all connections simultaneously reduce their transmission window size, leading to a severe drop in throughput at the same time. On the other hand, Drop Tail or Random Drop strategies are very sensitive to sudden flows; that is, the gateway queue will often overflow when packets from these flows arrive. To avoid these two phenomena, gateways can use special algorithms to detect congestion and decide which connections will be notified of congestion at the gateway. The RED gateway randomly selects incoming packets to mark; with this method, the probability of marking a packet from a particular connection is proportional to the connection's shared bandwidth at the gateway.
− Another goal is to control the average queue size even without cooperation from the source entities. This can be done by dropping packets when the average size exceeds an upper threshold (instead of marking it). This approach is necessary in cases where most connections have transmission times that are less than the round-trip time, or where the source entities are not able to reduce traffic in response to marking or dropping packets (such as UDP flows).
3.2.2 Algorithm
This section describes the algorithm for RED gateways. RED gateways calculate the average queue size using a low-pass filter. This average queue size is compared with two thresholds: minth and maxth. When the average queue size is less than the lower threshold, no incoming packets are marked or dropped; when the average queue size is greater than the upper threshold, all incoming packets are dropped. When the average queue size is between minth and maxth, each incoming packet is marked or dropped with a probability pa, where pa is a function of the average queue size avg; the probability of marking or dropping a packet for a particular connection is proportional to the bandwidth share of that connection at the gateway. The general algorithm for a RED gateway is described as follows: [5]
For each packet arrival
Caculate the average queue size avg If minth ≤ avg < maxth
div.maincontent .s1 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 15pt; }
div.maincontent .s2 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 15pt; }
div.maincontent .p { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; }
div.maincontent p { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; }
div.maincontent .s3 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 14pt; }
div.maincontent .s4 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; }
div.maincontent .s5 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; }
div.maincontent .s6 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: bold; text-decoration: none; font-size: 14pt; }
div.maincontent .s7 { color: black; font-family:Wingdings; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; }
div.maincontent .s8 { color: black; font-family:Arial, sans-serif; font-style: italic; font-weight: bold; text-decoration: none; font-size: 15pt; }
div.maincontent .s9 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 14pt; }
div.maincontent .s10 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 9pt; vertical-align: 6pt; }
div.maincontent .s11 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 13pt; }
div.maincontent .s12 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 10pt; }
div.maincontent .s13 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-d -
Identify Rating Levels and Rating Scales
zt2i3t4l5ee
zt2a3gstourism,quan lan,quang ninh,ecology,ecotourism,minh chau,van don,geography,geographical basis,tourism development,science
zt2a3ge
zc2o3n4t5e6n7ts
of the islanders. Therefore, this indicator will be divided into two sub-indicators:
a1. Natural tourism attractiveness a2. Cultural tourism attractiveness
b. Tourist capacity
The two island communes in Quan Lan have different capacities to receive tourists. Minh Chau Commune is home to many standard hotels and resorts, attracting high-income domestic and international tourists. Meanwhile, Quan Lan Commune has many motels mainly built and operated by local people, so the scale and quality are not high, and will be suitable for ordinary tourists such as students.
c. Time of exploitation of Quan Lan Island Commune:
Quan Lan tourism is seasonal due to weather and climate conditions and festivals only take place on certain days of the year, specifically in spring. In Quan Lan commune, the period from April to June and from September to November is considered the best time to visit Quan Lan because the cultural tourism activities are mainly associated with festivals taking place during this time.
Minh Chau island commune:
Tourism exploitation time is all year round, because this is a place with a number of tourist attractions with diverse ecosystems such as Bai Tu Long National Park Research Center, Tram forest, Turtle Laying Beach, so besides coming to the beach for tourism and vacation in the summer, Minh Chau will attract research groups to come for tourism combined with research at other times of the year.
d. Sustainability
The sustainability of ecotourism sites in Quan Lan and Minh Chau communes depends on the sensitivity of the ecosystems to climate changes.
landscape. In general, these tourist destinations have a fairly high level of sustainability, because they are natural ecosystems, planned and protected. However, if a large number of tourists gather at certain times, it can exceed the carrying capacity and affect the sustainability of the environment (polluted beaches, damaged trees, animals moving away from their habitats, etc.), then the sustainability of the above ecosystems (natural ecosystems, human ecosystems) will also be affected and become less sustainable.
e. Location and accessibility
Both island communes have ports to take tourists to visit from Van Don wharf:
- Quan Lan – Van Don traffic route:
Phuc Thinh – Viet Anh high-speed boat and Quang Minh high-speed boat, depart at 8am and 2pm from Van Don to Quan Lan, and at 7am and 1pm from Quan Lan to Van Don. There are also wooden boats departing at 7am and 1pm.
- Van Don - Minh Chau traffic route:
Chung Huong high-speed train, Minh Chau train, morning 7:30 and afternoon 13:30 from Van Don to Minh Chau, morning 6:30 and afternoon 13:00 from Minh Chau to Van Don.
f. Infrastructure
Despite receiving investment attention, the issue of infrastructure and technical facilities for tourism on Quan Lan Island is still an issue that needs to be resolved because it has a direct impact on the implementation of ecotourism activities. The minimum conditions for serving tourists such as accommodation, electricity, water, communication, especially medical services, and security work need to be given top priority. Ecotourism spots in Minh Chau commune are assessed to have better infrastructure and technical facilities for tourism because there are quite complete and synchronous conditions for serving tourists, meeting many needs of domestic and foreign tourists.
3.2.1.4. Determine assessment levels and assessment scales
Corresponding to the levels of each criterion, the index is the score of those levels in the order of 4, 3, 2, 1 decreasing according to the standard of each level: very attractive (4), attractive (3), average (2), less attractive (1).
3.2.1.5. Determining the coefficients of the criteria
For the assessment of DLST in the two communes of Quan Lan and Minh Chau islands, the students added evaluation coefficients to show the importance of the criteria and indicators as follows:
Coefficient 3 with criteria: Attractiveness, Exploitation time. These are the 2 most important criteria for attracting tourists to tourism in general and eco-tourism in particular, so they have the highest coefficient.
Coefficient 2 with criteria: Capacity, Infrastructure, Location and accessibility . Because the assessment area is an island commune of Van Don district, the above criteria are selected by the author with appropriate coefficients at the average level.
Coefficient 1 with criteria: Sustainability. Quan Lan has natural and human-made ecotourism sites, with high biodiversity and little impact from local human factors. Most of the ecotourism sites are still wild, so they are highly sustainable.
3.2.1.6. Results of DLST assessment on Quan Lan island
a. Assessment of the potential for natural tourism development
For Minh Chau commune:
+ Natural tourism attractiveness is determined to be very attractive (4 points) and the most important coefficient (coefficient 3), so the score of the Attractiveness criterion is 4 x 3 = 12.
+ Capacity is determined as average (2 points) and the coefficient is quite important (coefficient 2), then the score of Capacity criterion is 2 x 2 = 4.
+ Exploitation time is long (4 points), the most important coefficient (coefficient 3) so the score of the Exploitation time criterion is 4 x 3 = 12.
+ Sustainability is determined as sustainable (4 points), the important coefficient is the average coefficient (coefficient 1), so the score of the Sustainability criterion is 4 x 1 = 4 points
+ Location and accessibility are determined to be quite favorable (2 points), the coefficient is quite important (coefficient 2), the criterion score is 2 x 2 = 4 points.
+ Infrastructure is assessed as good (3 points), the coefficient is quite important (coefficient 2), then the score of the Infrastructure criterion is 3 x 2 = 6 points.
The total score for evaluating DLST in Minh Chau commune according to 6 evaluation criteria is determined as: 12 + 4 + 12 + 4 + 4 + 6 = 42 points
Similar assessment for Quan Lan commune, we have the following table:
Table 3.3: Assessment of the potential for natural ecotourism development in Quan Lan and Minh Chau communes
Attractiveness of self-tourismof course
Capacity
Mining time
Sustainability
Location and accessibility
Infrastructure
Result
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
CommuneMinh Chau
12
12
4
8
12
12
4
4
4
8
6
8
42/52
Quan CommuneLan
6
12
6
8
9
12
4
4
4
8
4
8
33/52
b. Assessment of the potential for humanistic tourism development
For Quan Lan commune:
+ The attractiveness of human tourism is determined to be very attractive (4 points) and the most important coefficient (coefficient 3), so the score of the Attractiveness criterion is 4 x 3 = 12.
+ Capacity is determined to be large (3 points) and the coefficient is quite important (coefficient 2), then the score of the Capacity criterion is 3 x 2 = 6.
+ Mining time is average (3 points), the most important coefficient (coefficient 3) so the score of the Mining time criterion is 3 x 3 = 9.
+ Sustainability is determined as sustainable (4 points), the important coefficient is the average coefficient (coefficient 1), so the score of the Sustainability criterion is 4 x 1 = 4 points.
+ Location and accessibility are determined to be quite favorable (2 points), the coefficient is quite important (coefficient 2), the criterion score is 2 x 2 = 4 points.
+ Infrastructure is rated as average (2 points), the coefficient is quite important (coefficient 2), then the score of the Infrastructure criterion is 2 x 2 = 4 points.
The total score for evaluating DLST in Quan Lan commune according to 6 evaluation criteria is determined as: 12 + 6 + 6 + 4 + 4 + 4 = 36 points.
Similar assessment with Minh Chau commune we have the following table:
Table 3.4: Assessment of the potential for developing humanistic eco-tourism in Quan Lan and Minh Chau communes
Attractiveness of human tourismliterature
Capacity
Mining time
Sustainability
Location and accessibility
Infrastructure
Result
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Quan CommuneLan
12
12
6
8
9
12
4
4
4
8
4
8
39/52
Minh CommuneChau
6
12
4
8
12
12
4
4
4
8
6
8
36/52
Basically, both Minh Chau and Quan Lan localities have quite favorable conditions for developing ecotourism. However, Quan Lan commune has more advantages to develop ecotourism in a humanistic direction, because this is an area with many famous historical relics such as Quan Lan Communal House, Quan Lan Pagoda, Temple worshiping the hero Tran Khanh Du, ... along with local festivals held annually such as the wind praying ceremony (March 15), Quan Lan festival (June 10-19); due to its location near the port and long exploitation time, the beaches in Quan Lan commune (especially Quan Lan beach) are no longer hygienic and clean to ensure the needs of tourists coming to relax and swim; this is also an area with many beautiful landscapes such as Got Beo wind pass, Ong Phong head, Voi Voi cave, but the ability to access these places is still very limited (dirt hill road, lots of gravel and rocks), especially during rainy and windy times; In addition, other natural resources such as mangrove forests and sea worms have not been really exploited for tourism purposes and ecotourism development. On the contrary, Minh Chau commune has more advantages in developing ecotourism in the direction of natural tourism, this is an area with diverse ecosystems such as at Rua De Beach, Bai Tu Long National Park Conservation Center...; Minh Chau beach is highly appreciated for its natural beauty and cleanliness, ranked in the top ten most beautiful beaches in Vietnam; Minh Chau commune is also home to Tram forest with a large area and a purity of up to 90%, suitable for building bridges through the forest (a very effective type of natural ecotourism currently applied by many countries) for tourists to sightsee, as well as for the purpose of studying and researching.
Figure 3.1: Thenmala Forest Bridge (India) Source: https://www.thenmalaecotourism.com/(August 21, 2019)
3.2.2. Using SWOT matrix to evaluate Quan Lan island tourism
General assessment of current tourism activities of Quan Lan island is shown through the following SWOT matrix:
Table 3.5: SWOT matrix evaluating tourism activities on Quan Lan island
Internal agent
Strengths- There is a lot of potential for tourism development, especially natural ecotourism and humanistic ecotourism.- The unskilled labor force is relatively abundant.- resource environmentunpolluted, still
Weaknesses- Poorly developed infrastructure, especially traffic routes to tourist destinations on the island.- The team of professional staff is still weak.- Tourism products in general
quite wild, originalintact
general and DLST in particularalone is monotonous.
External agents
Opportunity- Tourism is a key industry in the socio-economic development strategy of the province and Van Don economic zone.- Quan Lan was selected as a pilot area for eco-tourism development within the framework of the green growth project between Quang Ninh province and the Japanese organization JICA.- The flow of tourists and especially ecotourism in the world tends toincreasing
Challenge- Weather and climate change abnormally.- Competition in tourism products is increasingly fierce, especially with other localities in the province such as Ha Long, Mong Cai...- Awareness of tourists, especially domestic tourists, about ecotourism and nature conservation is not high.
Through summary analysis using SWOT matrix we see that:
To exploit strengths and take advantage of opportunities, it is necessary to:
- Diversify products and service types (build more tourism routes aimed at specific needs of tourists: experiential tourism immersed in nature, spiritual cultural tourism...)
- Effective exploitation of resources and differentiated products (natural resources and human resources)
div.maincontent .p { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; } div.maincontent p { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; margin:0pt; } div.maincontent .s1 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 13pt; } div.maincontent .s2 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 13pt; } div.maincontent .s3 { color: #0D0D0D; font-family:"Times New Roman", serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 14pt; } div.maincontent .s4 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s5 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: bold; text-decoration: none; font-size: 14pt; } div.maincontent .s6 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; vertical-align: -3pt; } div.maincontent .s7 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; vertical-align: -2pt; } div.maincontent .s8 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; vertical-align: -1pt; } div.maincontent .s9 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s10 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 14pt; } div.maincontent .s11 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s12 { color: black; font-family:Symbol, serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s13 { color: black; font-family:Wingdings; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s14 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 9pt; vertical-align: 5pt; } div.maincontent .s15 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 9pt; vertical-align: 5pt; } div.maincontent .s16 { color: black; font-family:Cambria, serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s17 { color: #080808; font-family:"Times New Roman", serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 14pt; } div.maincontent .s18 { color: #080808; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s19 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 11pt; } div.maincontent .s20 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 10pt; } div.maincontent .s21 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: bold; text-decoration: none; font-size: 11pt; } div.maincontent .s22 { color: black; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; text-decoration: none; font-size: 11pt; } div.maincontent .s23 { color: black; font-family:"Times New Roman", serif; font-style: italic; font-weight: normal; text-decoration: none; font-size: 14pt; } div.maincontent .s24 { color: #212121; font-family:"Times New Roman", serif; font-style: normal; font-weight: normal; tex -
Division of common property between husband and wife according to the Law on Marriage and Family 2014 - 9
[81]
According to Table 2.1, the causes of domestic violence account for a large percentage of the husband's drinking (25.2%), when the wife argues back (23.4%), and according to the husband's feelings (22%). This shows that men in Korean society today still consider themselves the head of the family and the wife must follow all the decisions of the husband. The wife has no right to argue back with her husband. Moreover, everything the husband does is based on his feelings, if he is sad and angry for some other reason, he takes it out on his wife. The man uses alcohol to legitimize his violent actions. The patriarchal concept still exists in society from generation to generation.
Table 2.2 Statistics on the occurrence of domestic violence (Reasons for husband beating)
Reasons husband beats
Number | Ratio (%) | |
Argue with husband | 75 | 27.2 |
Despise husband | 64 | 23.2 |
Interfere with husband's activities | 33 | 12.0 |
Housework is not good | 20 | 7.2 |
For the husband's family is not good | 15 | 5.4 |
Poor child education | 12 | 4.3 |
Wife cheating | 17 | 6.2 |
Because of love | 11 | 4.0 |
Other reasons | 29 | 10.5 |
Total | 276 | 100 |
[81]
According to table 2.2, the rate of violence due to arguing with husband and disrespecting husband still accounts for the highest rate. Arguing with husband (27.2%), and disrespecting husband (23.2%), interfering with husband's daily life (12%). This number clearly affirms that men always want to show their authority and self-respect as the head of the family. They cannot accept it when their wives disrespect or argue with them.
Table 2.3. Investigation by the Korean Institute for Criminal Policy on the Causes of Violence and Victims
Reason for hitting
violent person
Ratio (%) | Reason for hitting Victim of violence | Ratio (%) | |
The problem of arguing with husband | 56.0 | Offensive personality | 58.8 |
The issue of respecting parents husband | 19.2 | Wife Suspicion | 31.8 |
Children problem | 9.6 | No economic capacity | 26.3 |
Poor housework | 20.5 | cheating husband | 9.3 |
Waste of living expenses | 11.6 | Wife cheating | 3.3 |
Wife cheating | 6.1 | Insecure husband | 53.3 |
Other reasons | 29.5 | Drink alcohol | 30.8 |
Inferiority of husband's family | 19.2 | ||
Husband career problem | 9.3 | ||
Other reasons | 6.3 |
[56]
Through the statistics table 2.3, factors such as arguing with the husband, insulting personality, husband's low self-esteem and drinking alcohol still account for the highest percentage. The results of the above statistics table are evidence to affirm that in Korean society, men always promote their role and position, giving themselves the right to decide everything in the family. From there, the relationship with the wife is like a superior and inferior relationship.
Table 2.4. According to statistical documents of the Korean Family Law Consulting Institute
Causes of domestic violence
Ratio (%) | |
The couple could not understand each other. | 47.6 |
Drink alcohol | 14.1 |
Different lifestyles and value concepts | 8.4 |
suspected disease | 7.6 |
Both families | 2.0 |
Violence by habit | 3.3 |
Child abuse | 4.5 |
Economic conflict | 7.3 |
Adultery | 5.0 |
[85]
In Table 2.4, the problem of misunderstanding between husband and wife accounts for the highest percentage of causes leading to domestic violence. This percentage accounts for 47%. Meanwhile, the cause of violence caused by drinking alcohol is second but only accounts for 14.1%.
The above statistics show that the theories about the causes of domestic violence are correct. The main cause is still the cause within the family. The husband, as the head of the family, cannot accept it when his wife argues back and disrespects him. And when the couple does not understand each other, the husband always thinks that using force is the fastest and most effective way to maintain power and find common ground in the family. Patriarchal attitudes and gender inequality are clearly demonstrated.
2.2. Causes and conditions of domestic violence in Vietnam
2.2.1. Objective causes and conditions related to the living environment
2.2.1.1. Causes and conditions from the family scope
- Patriarchal attitude:
Although society is increasingly developing and people's awareness is also changing, Vietnamese men still maintain a patriarchal attitude. In many places in the country,