• Journal of Digital Convergence
• /
• v.12 no.4
• /
• pp.75-84
• /
• 2014

MVNO(Mobile Virtual Network Operator) promotes service competition in mobile telecommunication market and provides various service and opportunities for consumers. This study attempts to identify MVNO Service users' motivational and dissatisfying factors in relation to their willingness for continued use of the service 새 activate MVNO service. Use motivation factors are found as customer service, user interface, easiness, economical efficiency, and dissatisfying factors are handset quality, customer service, social influence. Economic efficiency factor had an affirmative influence on the sustained use motivation of the service users. Among dissatisfying factors, users had a negative influence when they recognize that their neighboring people does not use MVNO service. Policy authorities concerned must excavate a new plan to improve distribution structure of handset and reduce wholesaling cost of the MVNO service. It is necessary for MVNO service provider to develop a new business model so that users can recognize MVNO service not as inferior service but as rational and attractive service.

• The Journal of the Korea Contents Association
• /
• v.20 no.9
• /
• pp.344-354
• /
• 2020

The purpose of this study was to examine the moderating effect of service value in the effect of service fairness on service quality and structural causal relationship between service quality and reuse intention of domestic airlines. The impact between the variables was analyzed using SPSS 21.0 and AMOS 21.0 based on a survey of 320 airline users. The results are as follow. First, all the three factors of airline service fairness had a significant effect on service quality. Second, out of the three service fairness factors, distribution fairness and interactivity, had a positive effect on reuse intention. On the contrary, interactive fairness had no significant effect on reuse intention. Third, airline service quality had a significant effect on reuse intention. Finally, there was a moderating effect of value orientation in the relationship between service fairness and service quality.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.6
• /
• pp.1143-1150
• /
• 2001

In this paper, we designed a downconverter for K-band satellite multipoint distribution service(SMDS). The designed downconverter consists of a low noise amplifiers, bandpass filter, stable local oscillator, drain mixer and If Amplifiers. Low noise amplifiers show 28㏈ gain and 1.5㏈ noise figure in the frequency range of 19.2㎓~20.2㎓, and a band pass filter has a -l㏈ insertion loss, and 18.25㎓ Stable local oscillator which is dielectric resonant oscillation, We obtained that the output power of the 18.25㎓ oscillation frequency is 0.5㏈m and the phase noise is the -84.67㏈c at 10KHz offset frequency. With the input RF signal the 19.2㎓~20.2㎓, conversion gain of the drain mixer shows 5㏈ at the Intermediate frequency range of 950MHz~1950MHz. We have proved that the designed downconverter satisfied the specification of a K-band satellite multipoint distribution service and it can be applied to the satellite internet receiver.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.4
• /
• pp.739-746
• /
• 2016

The real-time railway safety monitoring and control system is for prevention of safety accidents, and this system adopts DDS (Data Distribution Service) standard based data transmission method to support integrated management of data from existing on-site safety detection devices. In this paper, we introduce the design of DDS-based data specification from on-site signal equipment on the conventional railway. For this, we (1) design UML data model of KRS SG 0062 standard which defines existing data specification, (2) define DDS Topics for DDS transmission and map KRS model to DDS Topic model, (3) suggest data transformation rules and (4) design network control QoS polices. In addition, we analysis actual on-site log data and validate our data specification design. DDS-based data transmission enables data compatibility among on-site devices and the real-time railway safety monitoring and control system, and allows efficient network management for a large amount of data transfer.

• Journal of KIISE:Information Networking
• /
• v.32 no.3
• /
• pp.404-414
• /
• 2005

In the packet data network systems beyond 3G, the service quality of current users is affected by traffic load due to the packet burstiness. There also exists a hot cell problem, a well-known problem of cellular systems, caused by traffic centraliBation. Hot cell problem is one of the major reasons of degrading system performance because hot cell increases the call drop rate without fully utilization of system resource. Therefore, it is very important to distribute the traffic on the several neighboring cells so that system uses its resource effectively and maintains the quality of service. In this paper, we propose the adaptive handoff algorithms for distributing traffic in the packet data network systems. In addition, we propose a new load estimation method with MAC state diagram suitable for packet data network systems. Through the simulation results, we could find that proposed algorithm is able to improve efficiency of system resource and to assure the service quality of users through traffic distribution.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.9
• /
• pp.67-74
• /
• 2008

This paper proposes, designs and implements an architecture of a server involved with the network camera based video surveillance systems to solve common problems including lack of inter-network operability at the video information sharing, drawback of bandwidth and processing-overhead caused by increase of the number of users, and difficulty of continuous monitoring over changes of network configurations. The proposed saver was designed to manage and service numerous network cameras and users as well as solving the existing problems by providing video distribution facility. Through the empirical study after applying the implemented server to a real video surveillance system we proved that the server can provide reasonable service quality while it processes several hundreds of simultaneous user connections under persisting more than one hundred connections to network cameras. We expect the developed video distribution server to enhance service quality of the large scale video surveillance systems for citizen-wide services such as traffic reporting informatics or natural calamities supporting.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.967-970
• /
• 2005

Ubiquitous Computing appeared, and moth researches are gone to apply this in various field. Specially, physical distribution circulation service field is intelligence enemy while alternate existent bar code and induction of RFID(Radio Frequency Identification) technology that permit various service is gone vigorously. In this treatise designed data model and schema to progress research about Core Event Type of PML(Product Markup Language) that is object information expression language that is proposed Auto-Id Lab and EPCglobal Inc. to process information of physical object and EPC-lS(Electronic Product Code Information Services) that is information services component and applies in sea transport physical logistics distribution service field.

• KIPS Transactions on Computer and Communication Systems
• /
• v.7 no.9
• /
• pp.227-234
• /
• 2018

Guaranteeing the end-to-end delay deadline is an important issue for quality of service (QoS) of delay sensitive systems, such as real-time system, networked control system (NCS), and cyber-physical system (CPS). Most routing algorithms typically use the mean end-to-end delay as a performance metric and select a routing path that minimizes it to improve average performance. However, minimum mean delay is an insufficient routing metric to reflect the characteristics of the unpredictable wireless channel condition because it only represents average value. In this paper, we proposes a deadline-aware routing algorithm that maximizes the probability of packet arrival within a pre-specified deadline for CPS by considering the delay distribution rather than the mean delay. The proposed routing algorithm constructs the end-to-end delay distribution in a given network topology under the assumption of the single hop delay follows an exponential distribution. The simulation results show that the proposed routing algorithm can enhance QoS and improve networked control performance in CPS by providing a routing path which maximizes the probability of meeting the deadline.

• Journal of Navigation and Port Research
• /
• v.34 no.1
• /
• pp.1-8
• /
• 2010

Electronic Navigational Charts(ENCs) are a database for the use of supporting the safety of navigation in marie voyage embedded within the navigational information in the Electronic Chart Display & Information System(ECDIS). Recently IMO made a decision on the mandatory equipment resolution of ECDIS for the international SOLAS vessels until 2018. With this regulation intention together the spontaneous uses from the wide range of marine applications are accelerating the increasing demand for ENCs at both of the navigational purpose and the non-navigational purpose. But there seems to be not enough guidelines or systematic approach for the service of the non navigational purpose. This paper deals with ENCs distribution issues. We present a integrated solution for the ENCs service of both user domains and also demonstrate the implemented results.

• Journal of Research and Publication Ethics
• /
• v.2 no.1
• /
• pp.19-24
• /
• 2021

Purpose: The purpose of this study is to check the direction of KODISA's pursuit of complex and convergence studies by confirming the research trends of KODISA's direct academic journals such as JDS, JIDB, JBEES and JAFEB. To this end, we tried to compare and confirm the research trends of the papers in four academic journals targeting keywords. Research Design, data and methodology: The analysis was conducted from 2014 to 2020 on 867 papers from JDS, 315 papers from JIDB, 120 papers from JBEES, and 867 papers based on the publication year of the most recently published journal from JAFEB. For the analysis, frequency analysis, word crowding, topic modeling, and frequency analysis by applying weights for each year group were performed on the keywords crawled using Python. Results: The results of frequency analysis showed that each journal is properly oriented toward its target direction. In addition, it was confirmed that the results of topic modeling significantly reflected the results of frequency analysis. Finally, it could be concluded that the results of frequency analysis using the weights of keywords by year group were also developing in the direction the target journals were analyzed. Specifically, in the case of JDS, 20 keywords such as Service Quality, Distribution were found to increase continuously according to the year group. Meanwhile, the keywords that continued to increase according to JIDB's year group were India, Social Capital, and Job Stress. The keywords that continued to increase according to the year group of JBEES were Micro Finance Institutions and Microfinance, and the keywords that of JAFEB were confirmed to be Vietnam and Service Quality. Conclusion: It was confirmed that KODISA's direct management journals responded appropriately to convergence issues. In particular, it was confirmed that researches in various fields of JDS are continuously increasing. However, it seems that JIDB needs to deal with various issues additionally in the service industry field and JBEES in the environment field. Finally, it was found that JAFEB needs to be wary of the relatively low level of interest in some countries such as Kazakhstan and India in recent years.