• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.40-50
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• 1999

The novel network architecture is recently required to accommodate a variety and intelligence of communication services. It is also required to provide customized network functions and to efficiently satisfy a various user's requirements. Accordingly, open network architecture based on ATM transport network features has been mainly studied in communication network. This paper evaluates the VSN(Virtual Switch Network) characteristics in the call processing of IMT-2000 switching system, which is composed of VSN instead of ATM switch network. VSN means switch network which is composed of ATM transport network. As a result, this paper proposes new VSN based ATM-MSC architecture with integrated call and connection control systems. and evaluates call processing delay characteristics using call process procedures. Internal call processing delay is increased approximately 3.5msec than the conventional ATM switching system. The experimental values applied in the analysis condition are the load 0.8, and the 100km distance between CCCPs(Call and Connection Control Processors) and VSNs. It is confirmed that the VSN has the potentiality in the practical implementation.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.163-176
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• 2015

The purpose of this research is to find out the service quality dimensions and detailed elements of a call center, and to study what relationship the service quality dimensions have with service recovery and customer royalty. This research set up the hypothesis and the research model to verify the relationship between the call center service quality and the service quality customer royalty for 139 people surveyed who experienced dissatisfactions. The result of the hypothesis verification shows that it has an influence on the counselors' service quality and service recovery processes of 3 call centers. The service recovery has en influence on the customer royalty. The result quality as a result remained for a customer after counseling can be called the ultimate purpose of using the call center for a customer, and the research shows that it has the largest influence on the service recovery of 3 dimensions of the call center service quality. In the relationship between the service recovery and the customer royalty, the service recovery has a meaningful influence on the customer royalty.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6A
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• pp.565-572
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• 2007

3G Long Term Evolution (3G LTE) is a next generation cellular networks system capable or providing various mobile multimedia services by using OFDMA and MIMO based radio access technology. Among many differences from existing WCDMA based systems, the facts that 3G LTE uses Physical Resource Block (PRB) as its radio resources and provides all services through the PS domain make the development of new resource management schemes necessary. This paper proposes an adaptive partitioning based downlink call admission control scheme. It separates realtime call requests from non-realtime ones, specifies maximum allowable resource amounts for each type, but if the maximum is exceeded, call requests are accepted with probability proportional to remaining resource amounts. Despite the fact that such adaptive concept has been already adopted by other call admission schemes, the contributions of our paper, which are that we are able to find an efficient way to apply the proposed scheme exploiting PRB characteristics and measure the resource usage of base stations by PRB utilization and payload ratio, are still valid. When judging from simulation results in comparison with others, our scheme is able to prioritize realtime call requests over non-realtime ones, and at the same time, overall system performance is superior.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.5
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• pp.881-893
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• 2020

CFI(Control Flow Integrity) is a mitigation mechanism that protects programs by verifying control flows. IFCC(Indirect Function Call Checks) and SCS(Shadow Call Stack), CFI supported by LLVM Clang compiler, were introduced to protect applications in Android. IFCC protects function calls and SCS protects function returns. In this paper, we propose attacks to bypass CFI on the application environment with IFCC and SCS. Even if IFCC and SCS were applied to user applications, it was confirmed that there were many code segments not protected by IFCC and SCS in the application memory. We execute code in CFI unprotected segments to construct 1) bypassing IFCC to call a protected function, 2) modulating return address via SCS bypass. We identify code segments not protected by IFCC and SCS in Android10 QP1A. 191005.007.A3. We also implement proof-of-concept exploits to demonstrate that modulation of control flow is possible in an environment where IFCC and SCS are applied.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2070-2079
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• 1997

In this paper, we proposed the FNCAC (fuzzy neural call admission control) scheme of the ATM networks which used the benefits of fuzzy logic controller and the learning abilities of the neural network to solve the call admission control problems. The new call in ATM networks is connected if QoS(quality of service) of the current calls is not affected due to the connection of a new call. The neural network CAC(call admission control) system is predictable system because the neural network is able to learn by the input/output pattern. We applied the fuzzy inference on the learning rate and momentum constant for improving the learning speed of the fuzzy neural network. The excellence of the proposed algorithm was verified using measurement of learning numbers in the traditional neural network method and fuzzy neural network method by simulation. We found that the learning speed of the FNCAC based on the fuzzy learning rules is 5 times faster than that of the CAC method based on the traditional neural network theory.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.557-567
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• 2018

There are currently various file encryption solutions for encrypting and storing files on disk. However, the existing file encryption solutions handle encryption and decryption all at once by file or directory. In this paper, we propose a system call supporting partial encryption function of the file. The user sets the encryption information with the system call interface at a portion where encryption of the file data is desired. And then the user writes file data, the data is encrypted and stored. Also if the user sets decryption information and reads the file data, the necessary part is decrypted by applying the set information. For the proposed system call, It consists of inspection module, management module, encryption module, decryption module, and HMAC module as per required system call. And it was implemented on the Linux environment. Also the operation of implemented system call was verified on the development board, and the performance was analyzed by measuring performance speed.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.87.2-87
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• 1996

• Environmental Analysis Health and Toxicology
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• v.31
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• pp.22.1-22.7
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• 2016

Objectives This study analyzed the associations between mobile phone call frequency and duration with non-specific symptoms. Methods This study was conducted with a population group including 532 non-patient adults established by the Korean Genome and Epidemiology Study. The pattern of phone call using a mobile phone was investigated through face-to-face interview. Structured methods applied to quantitatively assess health effects are Headache Impact Test-6 (HIT-6), Psychosocial Well-being Index-Short Form, Beck Depression Inventory, Korean-Instrumental Activities of Daily Living, Perceived Stress Scale (PSS), Pittsburgh Sleep Quality Index, and 12-item Short Form Health Survey where a higher score represents a higher greater health effect. Results The average daily phone call frequency showed a significant correlation with the PSS score in female subjects. Increases in the average duration of one phone call were significantly correlated with increases in the severity of headaches in both sexes. The mean (standard deviation) HIT-6 score in the subgroup of subjects whose average duration of one phone call was five minutes or longer was 45.98 (8.15), as compared with 42.48 (7.20) in those whose average duration of one phone call was <5 minutes. The severity of headaches was divided into three levels according to the HIT-6 score (little or no impact/moderate impact/substantial or severe impact), and a logistic regression analysis was performed to investigate the association between an increased phone call duration and the headache severity. When the average duration of one phone call was five minutes or longer, the odds ratio (ORs) and the 95% confidence intervals (CIs) for the moderate impact group were 2.22 and 1.18 to 4.19, respectively. The OR and 95% CI for the substantial or severe impact group were 4.44 and 2.11 to 8.90, respectively. Conclusions Mobile phone call duration was not significantly associated with stress, sleep, cognitive function, or depression, but was associated with the severity of headaches.

• Journal of Information Technology Services
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• v.13 no.2
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• pp.219-250
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• 2014

Corporations look for their competitiveness in many different areas, and one of them is customer call center, which provides professional, special service to the customers. The importance and the value of realization of customer satisfaction at each call center have become significant as it plays a leading role and is responsible for customer recreation and follow-up services. This study held in-depth interviews with 3 groups of professional call representatives (categorized by experience) from popular property and life insurance companies in Korea who operate in and outbound calls. Three variables, emotional quotient, organizational citizenship behavior (OCB), and IT utilization skill, were selected and it was observed how these variables affect the job performance of in and outbound call center representatives. The importance of the relationship between the variables and the key factors in the future direction of improvement of the call center representative organization was analyzed. Emotional quotient refers to the ability to recognize and use the emotion of oneself and others. It was considered it would be effective in enhancing the counseling ability of call center representatives, This study identifies the effect of emotional quotient on job performance and organizational citizenship behavior, which is defined as actions outside of normative roles in the organization. Also, the study aims to prove the effect of emotional quotient on the rapidly developing IT utilization ability in relation to job performance. As a result, it was found that service career (3 months, 3 years, 10 years) had a significant effect on the key factors that affect the organization-emotional quotient, IT utilization skill, and OCB. Especially for OCB, it was considered relatively less important to the new employees, while it greatly affected the job performance, rate of settlement, and sustainment of the working life for those with longer experience. Also, the result of the interview for each variable differed by the service career. Emotional quotient, IT utilization skill, and OCB were close connection for the representatives with longer experience than for those with shorter experience. And the level of intimacy of their relationship with job performance was in proportion to the years of service. Thus, to secure stability for the call center representatives and enhance their job performance continually, the importance of emotional quotient and IT utilization skill shall be reflected in the operation process actively. In particular, in order to lead a organization with outstanding culture, a management system shall apply OCB from the recruitment process.

• 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.