• Journal of the Korea Society for Simulation
• /
• v.11 no.4
• /
• pp.33-41
• /
• 2002

One of the key issues in mobile communication system is how to predict the number of calls per each cell. It is an important parameter and usually assumed as random Poisson value. For effective management of cellular network, the average number of calls should be traced and the changes in the numbers need to be promptly detected. In this paper we propose an algorithm detecting the changes in the demands of the users using the technique proposed for point-of-change problem based only on the number of call arrivals. Computer simulation reveals that the proposed method can effectively detect the discord, and the developed model is very accurate as showing mostly less than 1% differences.

• Journal of Korean Society for Quality Management
• /
• v.17 no.2
• /
• pp.27-35
• /
• 1989

Software developers often allocate a significant amount of effort to software testing. But for most business-related software system it is natural to expect the continued discovery of defects after the software system is released into field. Such defects are usually very expensive to fix and have the potential to cause great damages to the users. It is important to stop testing the software and release it to the users at the correct time. In this paper, we propose the determination of the optimal number of software test oy minimizing a total expected software cost. A numerical example is used when the criterion is the expected profit. The result indicates that the proposed software release policy based on the number of software test can be a good alternative to the existing policy.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.4A
• /
• pp.296-303
• /
• 2005

In this paper, we evaluate system performance and propose signal separation and detection when a user with one antenna shares the co-channel together with a user with two space-time coded antennas. The proposed technique can identify co-channel users by an interference cancellation method and detect the signals by maximum likelihood method. Simulation results show that the shortcoming of the Minimum Mean-Squared Error technique which can be applied two users with the same number of antenna but can not applied for heterogeneous MIMO users with the different number of antennas. Also, we apply the proposed scheme to OFDM system and evaluate the system performance. By simulations, we identify that the performance of the proposed system is the same as that of the existing single antenna users and improves the performance of the two-antenna MIMO users.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.10A
• /
• pp.952-959
• /
• 2006

In this paper, 2-D RAKE receiver simulator is made which beamforming technique is applied to in WCI)MA uplink basestation, and the performance is compared with that of 1-D RAKE receiver with varying the number of array elements, RAKE fingers and users. To model angular component of received signal and interfering signals due to multiple access, it is assumed that multiple users are located in the arbitrary direction of the same distance far from the basestation within a sector of the cell, and the channel simulator is made by using Geometry Based Single Bounce Elliptical Model(GBSBEM) suggested by Rappaport. BER performance is compared and analyzed with the various choise of the number of array elements, the number of RAKE fingers, the number of users and Eb/No. These results indicate that increasing the number of array elements eliminates efficiently multiple access interfering signals and improves dramatically BER performance.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.9
• /
• pp.927-935
• /
• 2010

In the era of Web 2.0, users create a number of their own Web contents. So, multimedia search becomes much more important than ever. A tag is a simple keyword which describes the Web contents including URL, pictures, and videos. Tags perform a role of descriptors of Web contents and Web metadata properly. If the number of tagged Web data increases, users are more likely to find the desired search result because the system includes the Web contents which have richer Web metadata. However, the number of users who use tags as Web metadata is relatively small. Because of the cumbersome process of adding tags, or users do not know what to add for the better accessibility from the public. Given situation, tag recommendation, which helps the process of adding tags, has been studied to solve these problems. When a user adds some Web contents, the tag recommendation system recommends relevant tags for the Web contents to the use, and the user selects recommended tags. We analyze and categorize various tag recommendation algorithms in tagging system.

• Information Systems Review
• /
• v.22 no.4
• /
• pp.93-113
• /
• 2020

This study investigates how the users' perceptions on like function in social media affect their attitudes toward the number of likes they receive from others. People conveniently believe that the number of likes is a significant measure of their online content quality and popularity. However, we take an ambivalent view that people do not settle their perceptions on the likes but change their like assessments according to circumstances. Specifically, we propose a model wherein emotional responses to the received likes may affect the value assessment of the likes. Our model shows how people resolve their internal contradiction on the value of the likes by flipping the traditional cognition-to-emotion mechanism to emotion-to-cognition mechanism. We validate the reversed dynamics between judgements and feelings using the data collected from 548 social media users. Results confirm that social media users' attitudes toward likes is largely affected by their emotional responses to their received number of likes. The implications of this study explain social media users' ambivalent attitudes toward likes by showing how they adjust their individual like valuation using their emotional responses.

• The Korean Journal of Emergency Medical Services
• /
• v.3 no.1
• /
• pp.102-115
• /
• 1999

This study was performed to investigate transport activities and strategize improvement of 119 rescue. We reviewed emergency care records of users who were transported by 119 rescue of six agencies in Chungnam from July 13, 1998 to August 8, 1998. The results were as follows ; 1. In sex distribution of users, the male was 65.0%. And the highest age group among users was above sixties(21.6%), then thirties in second order(19.3%). Accident was 50.8% as occupied first cause of transport, and then acute disease 22.8%. The highest requester for 119 rescue call was patient's families(47.1%) and average number of 119 rescue users per day was 20.9. 2. The nonurgent state of users was 58.9%. The frequency of users was 26.0 persons at sunday in most frequently, weekend and holiday was more common than ordinary day, and most frequent weather state was cloudy(23.8 persons). 3. Total running distance of 119 ambulance was 7.0km in average. Call time by users was 20-24 hours most commonly(21.9%). In then running time by each transport stage, 8 minutes were taken from 119 call receipt to scene arrival, 13 minutes from scene arrival to hospital. The kinds of pre-hospital care by 119 rescuer was vital sign check(81.2%), wound dressing or fracture fixation(41.2%), airway maintenance and O2 supply(30.4%).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.3
• /
• pp.663-670
• /
• 2015

In most public transportation related master plans, decisions for investment priorities are initially made by facilities with lower installation rates or lower satisfaction (performance) levels. In general, the decisions are made without conducting importance factor analysis. In this study, a combined method of importance-performance analysis (IPA) model for bus users related in travel time is proposed by using Structural Equation Model (SEM). The results of the IPA for Metropolitan users show that the categories need improvement are number of bus stops, number of intersections, headways, waiting times for boarding and traffic signal operations in order. On the other hand, Non-Metropolitan uses show that the categories need improvement are traffic signal operations, waiting times for boarding, headways, bus exclusive lanes and number of intersections that is in reverse order to Metropolitan users.

• Journal of Korea Trade
• /
• v.26 no.5
• /
• pp.56-75
• /
• 2022

Purpose - This study examines the influencing factors of China's cross-border e-commerce exports in the context of the current situation and trends of China's cross-border e-commerce development. Through an improved trade gravity model, it provides more in-depth research and constructive opinions on the development of cross-border e-commerce in China. In this paper, factors such as consumption gap, volume of trade frictions, number of tourists, Internet usage and trade openness are added to the formula of the traditional trade gravity model in the improved trade gravity model to examine the influencing factors on China's cross-border e-commerce exports. Design/methodology - According to the empirical analysis, China's cross-border e-commerce exports to ten countries are used as dependent variables, and consumption gap, trade friction volume, trade distance, trade openness and number of Internet users are taken as independent variables. Regression analysis is conducted through a modified gravity model to test whether the hypotheses hold. Findings - The analysis shows that the hypothesis that China's cross-border e-commerce exports are influenced by trade openness, trade distance, consumption gap between trade parties, and the number of Internet users in the importing country is supported by these four hypotheses, but not all independent variables have an impact on them. Specifically, the number of travelers, trade frictions do not have an impact on China's cross-border e-commerce. That is to say, trade friction between China and the United States and political issues such as China-India and China-Japan territorial disputes that emerged before do not affect the development of cross-border e-commerce in China. Originality/value - The analysis shows that the factors influencing China's cross-border e-commerce exports are the trade openness of the importing country, the trade distance, the number of Internet users in the importing country, and the consumption gap between the two sides of the trade. The trade openness and the number of Internet users positively contribute to China's cross-border e-commerce, while the consumption gap and trade distance are negatively related to them. And the analysis found that the Sino-US trade war and the Sino-Indian territorial disputes and other trade frictions to China's cross-border e-commerce exports did not have a substantial impact.

• The Journal of the Korea Contents Association
• /
• v.16 no.4
• /
• pp.434-441
• /
• 2016

Using bigdata analysis procedures, the present study sought to review and explore the various aspects of self-disclosure and boundary impermeability of worldwide twitter users. A total of 415 million tweets issued by 54 million users were collected during 6 months and the users of top 10 languages were investigated. And the effect of languages of twitter users on the boundary impermeability, disclosure rate of user profile, profile image, geographical information, URL in profile and user description were analyzed in this study. The results showed that the boundary impermeability and all the self-disclosure rates of twitter users (profile, profile image, geographical information, URL in profile, user description) were significantly (p<0.001) different among language groups of users. The self-disclosure rates and the average points of Portuguese, Indonesian and Spanish users were higher than those of Arabic, Japanese, Turkish and Korean users. The results also showed a positive relationship between boundary impermeability and the number of tweets (including retweets) issued by each users.