• The Korean Journal of Ecology
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• v.23 no.4
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• pp.309-313
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• 2000

Since specific types and physical characteristics of anuran calls can represent reproductive qualities of a calling male, anuran calls have been studied in context of mate choice. We in here report call types of Rana dybowskii and their variations from two different recording sites. Calls of R. dybowskii are classified to three types based on their physical characteristics and behavioral observations; 'A-call'functions to advertise locations of a calling male and to attract potential mates. A territorial male emits 'B-call'only during male-male interaction. 'C -call'is released when a male frog was clasped by another male. The A-call from two recording sites, Miwon and Wonju, shows high variations in their call characteristics.

• IE interfaces
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• v.9 no.3
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• pp.168-179
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• 1996

Automatic repeated recalling from individual computing equipments such as PC and workstations, to access ATM networks may result in call overload to networks. Call overload causes to waste network resources and fail to meet user call processing QoS requirements. We evaluate two call connection request methods: the back-off recall method(BRM) which makes recall with random waiting time after rejection, and the direct recall method(DRM) which repeats call connection request whenever call request is rejected. We evaluate their performances by simulation and it shows that as the total number of attached terminals to each access node increases, BRM performs better than DRM in terms of the call acceptance level and effective network bandwidth utilization.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.125-143
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• 2015

As improving the life quality of citizen because of development of Urbanization and Information, civil application service of public institutions has been changed. The government provides a 24-hour civil service of e-government, public institutions operate U-complaints call center to pursue a personalized service to customers. As customer service are diversified, the inconvenience of service is increased. Therefore, public institutions instituted U-complaints call center to solve increased complaints. In early days, public institutions operated simple call center. However, it became intelligent U-complaints call center by SNS. The more increase the importance of agents' contact customer service, the more increase Job Performance considered by Organizational Commitment & Job Satisfaction of call center agents. This study analyzed that applied to Fairness Theory with Organizational Commitment, Job Satisfaction and analyze U-complaints call center agents' role and job performance of public institutions. Proposed a research model applied to job satisfaction with key variables, organizational commitments, job satisfaction. It's expected to impact on job performance of U-complaints call center agents in public institutions. For empirical study of research model, conducted a survey of the U-complaints call center agents of public institutions. 170 samples were collected from the survey and analyze relationship between the factors. Procedural justice, distribution fairness, fairness interaction are significant influence on organizational commitment of parameters by analysis U-complaints call center agents. Procedural justice and fairness of interaction was found not to effect on parameters of job satisfaction. Also, parameter, organizational commitment have significant influence on job satisfaction. However, have no influence on job performance. Therefore, the parameters of job satisfaction have significant influence on job performance. Public institutions should adopt to improve the quality of citizen services through U-complaints call center agents.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.61-68
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• 2010

In this study, we analyzed the pulse-duration, pulse-interval and peak-frequency of echolocation call in three species as Rhinolophus ferrumequinum, Pipistrellus abramus, and Myotis macrodactylus. The peak frequency and pulse duration for above mentioned species were 69 kHz, 47 kHz and 49 kHz and $69.39{\pm}8.76\;ms$, $4.95{\pm}0.77\;ms$ and $3.09{\pm}0.48\;ms$ for R. ferrumequinum, P. abramus and M. macrodactylus, respectively. The pulse intervals for R. ferrumequinum, P. abramus and M. macrodactylus were $103.61{\pm}9.05\;ms$, $67.59{\pm}3.47\;ms$ and $66.35{\pm}4.96\;ms$, respectively. The pulse pattern of R. ferrumequinum was setting into a short FM call and linked to long CF call and went through the short FM call again. The pulse pattern of M. macrodactylus was comprised with serial short FM call and the CF call was not checked up in accordance with the spectrogram analysis. The long FM call and short CF call got join together for the P. abramus and the peak frequency was checked up at the pulse ending as CF call.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.316-323
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• 2002

In this paper, we analyze the call control scheme that is using buffer at new call and handoff call for non-uniform traffic load distribution, the multiple cell environments and the multiple types of services such as voice and data service. Considering the facts, the call admission control method using the effective bandwidth concept is employed in this paper, The bandwidth for a new call and a handoff call is allocated by the number of mobile station and dynamically assigned by taking account of the blocking rate of new calls and the dropping rate of handoff calls. The call control procedure is experimented through a simulation study by dynamically the bandwidth to new and handoff calls based on the blocking rate and the dropping rate. The results show our call control scheme can get a good quality of service for mobile users.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.357-362
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• 2009

We propose a method to recommend most likely people to call based on call log of mobile phone user. Call logs of an user can reflect calling pattern of the user include regular calling behavior. When user got a list of people to call with a click of 'send' button on the phone, the time and effort to search a person with several typing or to select a person from the list can be definitely reduced. This paper presents the design process of an algorithm to find most likely people to call at a certain moment and the verification process with recorded call log and Experience Sampling Method(ESM) on mobile phone.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.11
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• pp.2897-2908
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• 1996

This paper presents an effective call admission control algorithm using the Common Pool on the virtual path in ATM networks. Call admission control decides whether or not to accept a new call, so as to ensure the service quality of both individiual existing calls and of the new call itself. In the proposed algorithm, a new call is accepted when the sum of the bandwidths of existing calls and of the new call will not exceed lind capacity. If the sum of their bandwidths exceed link capacity, reserved bandwidth of Common Pool is considreed to accept the new call. Computer simulation results using a simuple network model are algorithm given to evaluate accuracy and call blocking probability by the proposed method.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1217-1226
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• 2000

Traditionally, Mobile Teletraffic model consists of two sub-models, i.e. the network traffic model and the traffic source model. In this paper, we present the traffic source model by developing MobCall (Mobile Call Simulator) which analyses various mobile wireless environments based on regional characteristics that the base stations are located. User mobility is presented by regional average vehicle speeds and the transportation share rate. Moreover, the user mobility on subway, which is increasing in urban area, is considered in MobCall. And also, user's movements on highway are considered in MobCall. The object-oriented simulation platform, C++SIM, is used to implement MobCall. Using MobCall, the accumulated number of calls in residential and commercial regions, the handoff rate with respect to traffic sources of Seoul, the handoff rate on highway, and the handoff rate according to the call duration are presented. MobCall enables the simulation of dynamic handoff buffering and functional entity control of one base station according to the changes in user's calling pattern at the design phase. Also, when a new town is under construction by a detailed plan, MobCall is used to design the mobile network with regional characteristics and user mobility considered.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.316-321
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• 2008

In the present emerging global economy, as the focus is shifted from manufacturing to service sector, the efficiency of service operations is crucial for the county's sustainable growth and development. As one of the fastest growing service sector industries in South Korea, the call center has become an inevitable part of customer service for most companies. Despite of the strategic importance of the call center, there has been no empirical study on the efficiency of call center service operations in the literature. The main purpose of this study is to evaluate the technical efficiency of call center services so as to not only identify the current status of call center service operations, but also suggest ways to improve service operations efficiency. For this purpose, we apply a non-parametric efficiency measurement method, DEA (Data Envelopment Analysis), to domestic call centers in order to compare their relative efficiency. Based on DEA evaluations, we provided specific directions for the inefficient call centers to possibly improve their operation efficiencies. It is expected that the measurement methods suggested in this study can be applied to various issues such as service KS certification, service operations management, and the productivity analysis of service personnel.

• Journal of the Korean Data and Information Science Society
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• v.23 no.4
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• pp.777-785
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• 2012

Recently, the rapid development of internet and information technology has led to rapid changes in many industries. One of the most rapidly developing industries is the call centers. Almost all public institutions, financial institutions including insurance companies, and shopping malls, many call center staffs are proceeding with the consultation. However, lack of call center staffs is leading to a lot of customers complaints. The function of outbound call centers such as promotion and sale of products is also arising some problems due to insufficient number of consulting staffs. In this study, we propose the call center model for maximizing the rate of call connection time and suggest the best way of call centers model to be the channel distributions using the data mining techniques.