Overview of Previous Studies

CHAPTER 1: OVERVIEW OF PREVIOUS STUDIES

1.1. Overview of foreign research

Mitchell, F. and Reid, GC (2000), found that the relationship between benefits - costs and the level of market competition are two factors affecting KTQTCP. The factor of the relationship between benefits and costs shows that managers always want to achieve the goals of control and cost savings to achieve maximum profits. The application of cost management accounting aims to consider the effectiveness of cost use at each stage and each department, ensuring the benefits from spending costs to the efficiency of the enterprise's production and business activities. The provision of cost information is always of interest to business managers in each department and management level. When considering the application, always set the goal of spending costs to ensure benefits for the enterprise. Always set the goal of saving and strictly controlling to maximize profits, simplify the enterprise apparatus, eliminate unnecessary and ineffective activities. The information provided to managers must be simple, accurate, and must be the most useful information. Market competition level factor: the more competitive the market is, the more businesses must constantly innovate to survive and develop. The level of competition shows the attention of businesses in learning about how customer needs change, combined with the company's resources to achieve the most optimal business efficiency. Promoting market competition level is a revolution in the process of competition, innovation and creativity with increasingly modern techniques and technologies. Recognizing the level of influence of this factor helps businesses find the causes to improve and enhance management work appropriately.

Drury, C. (2001), identified two factors: the level of market competition and the specific factor of the business sector, which deeply affect cost management. Sharing the same view with Abdel-Kader and Luther, R. (2006), the factor of market competition has an impact on cost management, the level of market competition is the enterprise's research, study of information and knowledge to complete the set goals, this factor also affects financial activities, strategies in cost management, the higher the competition, the more the enterprise is motivated.

Constantly innovate and improve to survive and develop throughout the business process. Industry-specific factors: each industry has different characteristics in terms of production and business organization structure, so the perception and application of cost management, management methods or cost allocation methods will also be different, information from KTQTCP is considered in the relationship between accounting and management levels, this factor affects the development of the enterprise because each different industry will affect the classification and recording of costs, in the business process the relationship between accounting and other departments must be considered specifically, all stages have a mutual support relationship to form a unified entity, each enterprise has its own business line, input materials have too high value, or go through many processing stages, requiring enterprises to modernize from the production process to the management stage, applying modern science and technology, or non-production industries but related to finance, service business, are strongly affected by regulations, policies, requirements Business managers must be provided with complete, timely and quick information to achieve the goals of state agencies. This factor affects the identification, classification and cost accounting according to the correct business lines of the business.

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• Overview of Previous Studies
• 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
• Studies on the Application of Balanced Scorecard in Strategic Management at Foreign Enterprises
• Perfecting the Organization of Applying the Production Cost Accounting Method to Serve Cost Management Accounting
• Overview of Theoretical Studies on Social Security

Hansen, D. and Mowen, M. (2003), found that the factor of applying information technology in KTQTCP has a great influence on recording, processing and providing accurate and timely information, improving efficiency in cost management, helping enterprises achieve the set goals. Science and technology or information technology helps improve processing, provide timely and complete data to administrators, applying technology to synchronize the operating apparatus of enterprises is very necessary, from production to management, helping the information processing process to be quick, the data is reported accurately according to the actual operating status, helping towards remote management, solving difficulties in production and business activities to improve enterprise efficiency.

Laitiner, EK (2003), stated that factors such as the level of market competition show that the greater the competition between businesses, the more businesses must always

Find ways to innovate and improve to survive and develop, find out the causes affecting the competitiveness of enterprises from customers and competitors, apply reality to your enterprise to be able to meet the maximum requirements of customers. The factor of the relationship between benefits and costs affects the work of the enterprise's cost accounting, with the view that the cost must bring certain profits to the enterprise, the enterprise controls and reduces costs to maximize profits, the search and detection of unnecessary costs to eliminate, the administrator needs to be provided with accurate and timely information from the cost accounting for making decisions to handle unnecessary costs to maximize profits for the enterprise.

Chenhall, RH (2004), stated that there are 3 factors affecting KTQTCP including: business strategy, level of accounting staff in the enterprise, implementation method. Business strategy factor: decisions of managers are important factors in implementing business strategies, implementation of cost management in business strategy is the most important factor of business administrators, decisions in business strategy of managers affect cost implementation, the ultimate desire of administrators is always to maximize profits, so it is necessary to consider the use of costs for the set goals. The factor of accounting staff qualifications in the enterprise is the ability, responsibility and ethics of accounting staff in performing tasks, predicting the ability and efficiency in work, or qualifications are knowledge, skills, experience, and personality, these abilities all have a great impact on the work of accounting and financial management of the enterprise, always improving personal capacity all have an impact on cost control. Implementation method factor: agreeing with Lawson, there needs to be a combination of methods, depending on the design of each enterprise's method, which will help the cost control system achieve the most optimal efficiency.

Abdel-Kader and Luther, R. (2006), pointed out that the customer resource factor affects the application of cost accounting, the more customer demand increases, the greater the competition in the market, requiring businesses to make wise decisions, strengthen cost control to set appropriate selling prices, satisfy customer needs, managers must apply cost accounting to

To improve and enhance the efficiency of production and business activities, customer needs and competitors' strategies strongly affect the decisions of enterprises. The more diverse and rich these needs are, the faster and more accurate information managers need to have about KTQTCP to promptly make decisions in the process of managing and operating the enterprise.

Lawson, RA et al. (2010), identified two factors affecting KTQTCP including: business strategy, implementation method. Business strategy factor: managers must consider the costs related to the goals to be implemented in the proposed business strategies, actions and strategies always have mutual impact, well-controlled costs help managers operate effectively while improving competitive position in the market. Implementation method factor: there are many different cost control methods, each enterprise can implement different methods to implement specific situations suitable for its enterprise, all focus on management, regulation and cost control, must combine methods, depending on each condition, the enterprise proactively establishes methods, will help the enterprise improve operational efficiency, depending on the type of enterprise, to improve management efficiency, it is necessary to combine methods with the choice of methods to suit the actual situation of the enterprise.

Ulf Diefenbach, Andreas Wald, Ronald Gleich (2018) identified four factors affecting the management of the enterprise: management organization, information needs, implementation methods, and enterprise culture. Management organization factor: cost control is reflected in the management organization and processes, regulations, as well as specific responsibilities, the cost control system is designed to be decentralized or centralized, business operations must be standardized and strictly controlled, helping managers evaluate, and consider cutting or regulating costs in which process is appropriate. Information need factor: providing information in the management of the enterprise is a prerequisite for managers to plan, implement and check plans by, during the implementation process, based on the information provided from the management of the enterprise, managers make decisions to adjust or handle in order to

The purpose of achieving the goal, therefore the quality of information provided determines the quality of the solutions proposed. The implementation method factor: in line with the above studies, the implementation methods of enterprises all affect the cost management, the methods chosen to implement for different goals of the enterprise, the administrator must choose the method that is suitable for the enterprise, the administrator all want to improve management and cost control, so choosing different methods to handle situations that occur in the production and business process is always the top goal. The cultural factor in the enterprise, all the implementation behaviors in the enterprise related to cost regulations affect cost control, the regulations in the production and business processes must always have the awareness of improvement so that in the implementation process, costs can be controlled most effectively, in addition, the enterprise culture also affects the business strategy and the information that the administrator needs to make decisions.

1.2. Overview of domestic research

Pham Thi Kim Van (2002) pointed out the importance of implementing and applying cost accounting in tourism companies, classifying specific costs to help businesses apply them immediately in practice, presenting issues in the process of organizing cost accounting, limitations in tourism businesses that have affected business results, and at the same time providing solutions such as proposing to make estimates of costs and revenues, determining business results, costs must be classified specifically and in detail according to their true nature to help managers better control, classify by each cost calculation object, establish procedures and order of cost aggregation in the tourism industry, clearly define cost calculation methods, in addition to cost accounting, it is also necessary to pay attention to management accounting for tourism revenue and results.

Tran Van Dung (2002), studied and researched cost accounting in calculating cost with the conditions of enterprises, studied the current situation of cost accounting organization and cost calculation at manufacturing companies, thereby giving opinions and specific solutions for each content, helping enterprises to be able to apply to improve the quality of cost control system at their own enterprises, the limitations of cost accounting affect

deeply affects the cost management of enterprises, administrators are always looking for solutions to improve production and business activities, specific contents of each stage are classified and allocated to the right specific objects to calculate the cost of production of products.

Pham Thi Thuy (2007), with her research on building a model of cost accounting in pharmaceutical manufacturing enterprises in Vietnam, has pointed out the cost accounting system in the pharmaceutical industry over the periods, and assessed the current status of cost accounting implementation in pharmaceutical manufacturing and trading enterprises which has not been effective, and has not helped managers make timely decisions. With its own characteristics, enterprises in the pharmaceutical manufacturing industry need to make estimates, classify cost items, apply scientific and technical advances to management, and cost accounting is a tool closely associated with the activities of enterprises.

Nguyen Quoc Thang (2010), organization of KTQTCP, product cost in enterprises in the plant seed industry in Vietnam, stated that enterprises in the plant seed industry need to strengthen and improve the management system, the quality of cost information is the basis for making short-term and long-term decisions, the combination of KTQTCP and product cost calculation in the plant seed industry will bring efficiency in control, as well as cost analysis, propose separating mixed costs into fixed costs and variable costs, along with establishing a management reporting system, and reporting management responsibility at plant seed enterprises.

Nguyen Hoan (2011), building a cost accounting model for confectionery manufacturing enterprises in Vietnam, identified three factors affecting cost accounting: managers' awareness of the cost accounting system, legal regulations related to the business sector and the qualifications of accounting staff. The author emphasized that managers with high management qualifications and well-trained staff are the best foundation for providing information on cost management and control. Research on the practice of cost accounting at confectionery manufacturing enterprises pointed out the limitations and proposed solutions related to the construction of a cost estimation system to measure and control at different stages.

Different stages and categories, with the characteristics of confectionery enterprises, managers can apply different production methods and forms, can hire or self-produce, production and processing must go through many stages to create semi-finished products, requiring the application of quality control work in each stage, each stage, controlling costs, eliminating unnecessary costs, improving the efficiency of business operations.

Nguyen Thi Bich Phuong (2013), research proposed some contents of cost accounting in Vinacomin open-pit coal mining enterprises, pointed out that cost accounting work includes the system of books, accounting documents, cost classification, cost estimates, analysis of fluctuations affecting costs, and organization of cost information system. The organization of cost accounting work is only in the early stages of formation, without a clear and specific orientation, therefore the cost information provided to managers is not effective and has many limitations. In addition, the study has proposed solutions to improve cost accounting work in coal mining enterprises such as: proposing to organize the cost accounting apparatus according to the model of combining financial accounting and management accounting, supplementing and perfecting the accounting system in identifying and classifying costs, issues of cost allocation, perfecting the information system for managers. For effective implementation, there needs to be synchronous coordination at all levels. Reality also shows that the production and business activities of coal mining enterprises are very diverse, influenced by many subjective and objective factors.

Nguyen Hai Ha (2016), perfecting the cost accounting in Vietnamese garment enterprises, identified 5 factors affecting the cost accounting in garment enterprises including: information needs, accounting staff qualifications, application of information technology systems, managers' awareness of the cost accounting system, production process. Analyze the impact of information provision on the organization of cost accounting. Garment enterprises need to perfect the cost accounting work, recommend combining the application of the ABC model in the organization of cost accounting, need to promote the organization, identification, classification of costs, application of cost norms in control, perfect

The system collects KTQTCP information, completes cost information analysis, and improves efficiency in the process of making implementation decisions.

Tran Ngoc Hung (2016), studying the factors affecting the application of management accounting in small and medium enterprises in Vietnam, determined that there are 7 factors affecting management accounting in enterprises, including: the level of state ownership in enterprises, the level of market competition, corporate culture, awareness of managers, enterprise scale, costs for organizing management accounting, business strategy. Micro and small enterprises find it difficult to successfully apply management accounting, the awareness of business owners often does not appreciate the usefulness of management accounting technical tools, does not propose specific business strategies, the study recommends that instead of implementing the management accounting model, business owners should equip themselves with initial knowledge of management accounting, in order to control costs, develop strategies and business plans, improve operational efficiency, and increase competitiveness in the market. For medium-sized enterprises, it is advisable to apply a management accounting model, with a scale that is just enough for the enterprise, the model should not be organized too large, the cost is too high, but the efficiency is not too high, focusing on specific items, making estimates, reports, specific production and business plans, combining financial accounting with management accounting, taking advantage of the enterprise's existing resources to maximize profits.

Nguyen Thi Duc Loan (2019), factors affecting the application of KTQTCP in enterprises exploiting, processing and trading construction stone in the Southeast provinces, the author inherited previous studies and concluded 6 factors affecting KTQTCP in enterprises in the construction stone mining and trading industry including: business strategy, legal regulations on resource management and exploitation, control of environmental management costs, qualifications of enterprise accountants, awareness of KTQTCP, relationship between benefits and costs. The author has determined and measured the factors affecting the application of KTQTCP, studied the theoretical model showing the relationship between factors affecting the application of KTQTCP, enterprises in the industry can refer to and apply to be able to filter out appropriate and useful information to strengthen control to help enterprises develop sustainably, besides