• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.28-34
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• 2021

Internet Service Providers (ISPs) constantly endeavor to resolve network congestion, in order to provide fast and cheap services to the customers. This study suggests two models based on Markov chain, using three and four access attempts to complete the call. It involves a comparative study of four models to check the relationship between Internet Access sharing traffic, and the possibility of network jamming. The first model is a Markov chain, based on call-by-call attempt, whereas the second is based on two attempts. Models III&IV suggested by the authors are based on the assumption of three and four attempts. The assessment reveals that sometimes by increasing the number of attempts for the same operator, the chances for the customers to complete the call, is also increased due to blocking probabilities. Three and four attempts express the actual relationship between traffic sharing and blocking probability based on Markov using MATLAB tools with initial probability values. The study reflects shouting results compared to I&II models using one and two attempts. The success ratio of the first model is 84.5%, and that of the second is 90.6% to complete the call, whereas models using three and four attempts have 94.95% and 95.12% respectively to complete the call.

• IE interfaces
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• v.18 no.3
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• pp.327-332
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• 2005

The call-attempt behavior in a telecommunications service is influenced by the launch of new services and the choice of subscribers. On Feb 28, 2005, there was a disastrous shut-down of major local electronic switching systems (ESS) due to an abrupt increase of call-attempts. This incident turned out to be a strong proof that appropriate forecasting attempts are necessary not only for the capacity planning of network but also for the quality control of ESS. In this paper, forecasting models are first developed to estimate the daily ESS call-attempts and user retrial rates and then meaningful interpretations of results will follow. Finally future research topics will be presented.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2002.11a
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• pp.45-57
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• 2002

Since a new entrant in the telecommunications market requires time in order to construct its own network, a requirement on the incumbent operator to implement carrier selection and pre-selection can enable a new entrant to immediately attract customers and earn revenue. Carrier selection can normally be accomplished in two ways, on a call-by-call basis or through carrel pre-selection. Call-by-call selection allows customers to choose a new entrant rather than the incumbent carrier using a specific code designated to the new carrier each time a call is made. Carrier Pre-Selection, on the other hand, allows customers directly connect to the network of one provider to have access automatically to another company's services when they pick up the phone to make certain types of calls. The carrier pre-selection option is generally considered to be a second regulatory step following the implementation of the call-by-call carrier selection option. Carrier pre-selection with the ability to override on a call-by-call basis for long distance, international, local, and fixed-to-mobile calls has now been implemented in many EU countries. This paper attempts to identify the issues in introducing CPS and to draw policy implications from other countries' experiences.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.3
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• pp.135-151
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• 1998

The demand of large capacity in coming cellular systems makes inevitable the deployment of small cells, rendering more frequent handoff occurrences of calls than in the conventional system. The key issue is then how effectively to reduce the chance of unsuccessful handoffs, since the handoff failure is less desirable than that of a new call attempt. In this study, we consider the control policies which give priority to handoff calls by limiting channel assignment for the originating new calls, and allow queueing the new calls which are rejected at their first attempts. On this system. we propose the problem of finding an optimal call control strategy which optimizes the objective function value, while satisfying the requirements on the handoff/new call blocking probabilities and the new call delay. The objective function takes the most general form to include such well-known performance measures as the weighted average carried traffic and the handoff call blocking probability. The problem is formulated into two different linear programming (LP) models. One is based on the direct employment of steady state equations, and the other uses the theory of semi-Markov decision process. Two LP formulations are competitive each other, having its own strength in the numbers of variables and constraints. Extensive experiments are also conducted to show which call control strategy is optimal under various system environments having different objective functions and traffic patterns.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2605-2619
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• 1996

In this paper, we evaluated performance of mobile exchange control part. Queueing network model is used for modeling of mobile exchange control part. We developed a call control processing and location registration scenartio which has a message exchange function between processors in mobile exchange control part. A network symbol are used the simulation models that are composed of the initialization module, message generation module, message routing module, message processing module, message generation module, HIPC network processing module, output analysis module. as a result of computer simulation, we obtain the processor utilization, the mean queue length, the mean waiting time of control part based on call processing and location registration capacity. The call processing and location registration capacity is referred by thenumber of call attempts in the mobile exchange and must be satisfied with the quality of service(delay time).

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.462-469
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• 2007

ATM protocol has the techniques such as cell discarding priority, traffic shaping and traffic policing. ATM based MPLS(Multiprotocol Label Switching) is discussed for its provisioning QoS commitment capabilities, traffic engineering and smooth migration for BcN using conventional ATM infra in Korea. This paper proposes preventive congestion control mechanism for detecting HTR(Hard To Reach) LSP(Label Switched Path) in ATM based MPLS systems. In particular, we decide HTR LSP using real time signaling information(etc., PTI,AIS/RDI) for applying HTR concept in circuit switching to ATM based MPLS systems and use those session gap and percentage based control algorithm that were used in conventional PSTN call controls. We concluded that it maximized the efficiency of network resources by restricting ineffective machine attempts. Proposed control can handle 208% call processing and more than 147% success call, than those without control. It can handle 187% BHCA(Busy Hour Call Attempts) with 100 times less than use of exchange memory.

• Journal of Information Technology Services
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• v.12 no.3
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• pp.55-71
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• 2013

Mobile communication industry is attracting a lot of attention all over the world and is expected to continue developing endlessly with the current rapid development of IT industry. Nowadays, mobile communication companies of vietnam are competing about service quality in order to retain existing customers and improve customer satisfaction and customer loyalty. This study attempts to research about the effect of mobile communication service quality on customer satisfaction and affecting relationship between customers satisfaction and customer loyalty. In this research empirically examine how mobile communication service quality influence customer loyalty in Vietnam. To do this, after considering characteristics of mobile communication service quality, quality measurement instrument was designed including call quality, call charge, cellphone, added service quality, corporate image, employee's attitude, and behavior. The study finds that all factors of call quality, added servces quality, corporate image, employee's attitude and behavior have positive effect on customer satisfaction except call charge and customers satisfaction also effects customers loyalty positively. From these results, Vietnam domestic mobile communication companies and foreign companies can grasp the general information about Vietnam mobile communication industry, and then, establish customers satisfaction strategies more effectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.5
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• pp.431-441
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• 1997

In this paper, a performance evaluation method for the Trunked Land Mobile Radio System, so called TRS(Trunked Radio System), is presented. The proposed evaluation method employs LCD(Lost Call Delayed) system model and Erlang-C distribution. In this system, queues are used to hold call requests that are initally blocked. When a user attempts a call and a channel is not immediately available, the call request may be delayed until a channel becomes available. For evaluating system performance, therefore, the probability that any caller is delayed in the queue for a waiting time greater than t seconds is derived and simulated by using such parameters as total number of available channels, traffic load and average duration of a call. Furthermore, the performance of the message and the transmission trunked channel assignment strategies is compared. The performance simulation results show that transmission trunking is shown to be more efficient than message trunking.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.41-49
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• 2021

All application programs, including malware, call the Application Programming Interface (API) upon execution. Recently, using those characteristics, attempts to detect and classify malware based on API Call information have been actively studied. However, datasets containing API Call information require a large amount of computational cost and processing time. In addition, information that does not significantly affect the classification of malware may affect the classification accuracy of the learning model. Therefore, in this paper, we propose a method of extracting a essential feature set after reducing the dimensionality of API Call information by applying various feature selection methods. We used CICAndMal2020, a recently announced Android malware dataset, for the experiment. After extracting the essential feature set through various feature selection methods, Android malware classification was conducted using CNN (Convolutional Neural Network) and the results were analyzed. The results showed that the selected feature set or weight priority varies according to the feature selection methods. And, in the case of binary classification, malware was classified with 97% accuracy even if the feature set was reduced to 15% of the total size. In the case of multiclass classification, an average accuracy of 83% was achieved while reducing the feature set to 8% of the total size.

• ETRI Journal
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• v.19 no.3
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• pp.169-185
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• 1997

This paper presents the design concepts and the system architecture of a mobile exchange for CDMA Mobile System. The paper also discusses complex subsystems in this system and design concepts of these subsystems. To evaluate the performance of the CDMA Mobile System, we have performed a computer simulation based on the framework of the mobile exchange. Simulation results are presented in terms of network traffic load (call attempts per second) and database performance requirements (transactions per second.)