• Journal of the Institute of Convergence Signal Processing
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• v.15 no.1
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• pp.9-14
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• 2014

The path loss data was re-calculated according to the distance between the base station and a mobile station in the mobile telecommunications network. In this paper, the averaged path loss data was plotted with the conventional path loss models(free space, plane earth, Hata model ${\ldots}$). The standard deviations for the 2 Km, 1 Km, 0.5 Km-interval averaged path loss were 2.29 dB, 3.39 dB, 4.75 dB, respectively. Additionally, the derivative values for the 2 Km, 1 Km, 0.5 Km-interval averaged path loss were evaluated to find the positions with more than 1 times or 2times of the standard deviation. The situations with the sharply fluctuated path loss were calculated to 5 positions in the 2 Km interval, to 7 positions in the 1 Km interval, to 19 positions in the 0.5 Km interval, respectively. And, the exact distances between the base station and a mobile station were found with the sharply fluctuated path loss.

• 한국노년학
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• v.40 no.2
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• pp.291-309
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• 2020

In this study, the behavioral model of Andersen and Newman(1973) was applied to identify the factors influencing the use of senior centers by the elderly in the community, and the mediating effect of user satisfaction was improved to improve the satisfaction of seniors using the Senior Center and operate the Senior Center. This study attempted to suggest policy and practical alternatives for activation. The subjects were 578 elderly people using 2,283 senior centers in Busan. As a result, the factors influencing the total usage period of the Senior Center were analyzed by age and type of potential factors among the leading factors, and the factors affecting the total number of days of senior center usage during the week were gender, age, and education level among the preceding factors. Appeared. Factors affecting user satisfaction as a parameter were analyzed as subjective health status among gender, age, and desire factors among preceding factors. As a result of verification of mediating effect of user satisfaction, there was a partial mediating effect between age and total use of Senior Center, full mediating effect between gender and days of Senior Center use, and partial mediating effect between age and Senior Center use days. Analyzed. According to the purpose and main findings of the study, the policy and practical suggestions for activating the satisfaction and use of Senior Center are as follows. First, program development and support according to the characteristics of senior center users are required. Second, there is a need to characterize per-path according to senior center type and regional environment. Third, there is a need to improve and raise the support standards for senior center operating expenses.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.382-385
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• 2008

본 논문은 게임 풀이를 통해서 모델 체킹 도구의 특징을 분석한다. 도망자-추적자 게임은 격자 모양의 미로에서 도망자가 추적자를 따돌리고 탈출하는 게임이다. 도망자가 격자 상에서 한 칸 움직일 때, 추적자는 일정한 패턴을 가지고 두 칸 움직인다. 이 문제를 SMV와 SPIN 모델 체커로 모델링하고 검증하는 과정을 통해서 SMV와 Spin 모델 체커의 특징을 분석한다. 실험을 통해서 우리는 최단 경로를 찾을 경우는 SMV 모델 체커를 사용해야 하고, 가능한 경로를 빨리 찾는 경우는 Spin 모델 체커가 더 적합함을 확인할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.121-124
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• 2002

문서의 고정된 스키마 없이 사용될 수 있는 XML문서를 관계형 데이터베이스에 문서 자체의 구조 정보와 함께 효율적으로 저장하려는 연구가 계속되고 있다. 계층적인 형태의 XML 문서들을 구조 검색하기 위한 정규 경로식 질의들을 평면 구조의 관계형 데이터베이스에서 처리하기 위해서 많은 비용이 필요하게 된다. 따라서 본 논문에서는 다양한 정규 경로식 질의들을 질의의 특성에 알맞은 방법으로 처리하는 저장 모델과 질의 처리 모델을 제안한다. 제안된 모델은 정규 경로식 질의에 포함된 경로 연산자를 분석하여 부모-자식 관계가 아닌 조상-자손 관계 조사에는 $\theta$-조인을 이용하고, 부모-자식 관계 조사에는 동등(equi)-조인을 이용하는 SQL문으로 변환 처리하여 질의 처리 효율성을 높였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.848-854
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• 2014

A Meta-analysis refers to a statistical literature synthesis method from the quantitative results of many known empirical studies. We conducted a meta-analysis and review of external factors based on the technology acceptance model for Smartphone-related researches. This study surveyed 106 research papers that established causal relationships in the technology acceptance model published in Korean academic journals during 2008 and 2013. The result of the meta-analysis might be summarized that the playfulness has the highest effect size in the path from external factors to the perceived usefulness, with the effect size(0.536). Also the self efficacy showed the highest effect size(0.626) in the path from external factors to the perceived ease of use. Based on these findings, several theoretical and practical implications were suggested and discussed with the difference from previous researches.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.460-465
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• 2013

Radio propagation in a high-speed railway is affected by ground reflective waves that are due to irregular reflection by the railway track, which consists of rails, sleepers, and gravel. This paper provides a train radio propagation model that simulates an irregular track reflective wave as a random variable. A simulation study using the train radio propagation model shows that the path loss exponent is around 3.0, indicating a reduced path loss compared to the value of 4.0 in the general mobile radio environment. Regressive analysis of the received signal strength indicators measured in the Gyeongbu high-speed railway showed the results identical to those of the simulation. These results confirm the train radio propagation model and can be applied to the coverage estimation and the design of a train radio network.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.1
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• pp.53-63
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• 1999

ATM 네트워크에서 다양한 트래픽을 특성과 QoS 요구사항을 갖는 멀티미디어 서비스의 종단간 품질을 만족시키면서 망 자원을 효율적으로 이용하기 위해서는 가상경로(virtual path : VP) 의 적절한 배치 및 대역 할당을 통한 논리적 망의 구성, 호 접속 시의 종적 경로 설정, 그리고 그와 연계된 효율적인 동적 대역 관리가 필수적으로 요구된다. 본 논문에서는 새로운 호가 시도될 때 논리적 망의 설계에서 설정된 가상경로의 대역으로 호의 품질 요구사항을 만족 시킬수 없거나 또는 미리 설정해 놓은 가상경로연결(VP Connection) 이 존재하지 않을 경우에 물리적 링크의 잔여용량을 기반으로 적절한 가상경로를 선택하여 용량을 재조정하기 위한 최적 관리 모델로서 MHR (Minimum Hop Route), MCR(Maximum Capacity Route), 그리고 MRCR (MaxMin Residual Capacity Route)방식을 제안하고 이에 대한 최적화 정식을 제안하였다. 제안된 각 최적화 모델에 대한 해를 노드의 수가 m인 네트워크에서 O(m2)의 복잡도로 구할 수 있는 알고리즘을 제시하고 시뮬레이션을 통해 제안된 최적화 모델이 망의 성능에 미치는 영향을 평균 호 차단률 평균 이용 링크의 수 , 그리고 노드 쌍간의 호 차단률의 분산등에 의해 망 운용의 효율성과 공평성등을 비교분석하였다.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.83-90
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• 2010

The purpose of this study is to establish the standard of fire lane design to improve the performance of disaster prevention in local area. To accomplish it, we have focused on three research methods as below: first, we have expected disaster occurrence based on emergency tendency in local area; second, we have verified fire lane routes design through fire lane modeling and network analysis; third, we have quantitatively examined a possibility of danger of fire lanes through current road network modeling and analysis. The result of this study could be helpful to effective fire lane designs and quantitative analyses.

• Journal of Internet Computing and Services
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• v.4 no.6
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• pp.43-55
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• 2003

Workflow mining is a newly emerging research issue for rediscovering and reengineering workflow models from workflow logs containing information about workflows being executed on the workflow engine. In this paper, we proposed workcase mining which was used dependency among activities. Main purpose of this paper is to minimize discrepancies between the modeled workflow process and the enacted workflow process as it is actually being executed. That is, we can get a complete set of activity firing sequences on buildtime. Besides, we can discover from workflow logs that which path out of all reachable paths a workcase has actually followed through on runtime. For this purpose we proposed two algorithm, the one is 'Activily-Dependent Net Algorithm' and the other is 'E-Walk Series Analysis Algorithm'.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.157-167
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• 2023

The use of big data for transportation often involves using data that includes personal information, such as the driver's driving routes and coordinates. This study explores the creation of a route choice prediction model using a large dataset from mobile navigation apps using federated learning. This privacy-focused method used distributed computing and individual device usage. This study established preprocessing and analysis methods for driver data that can be used in route choice modeling and compared the performance and characteristics of widely used learning methods with federated learning methods. The performance of the model through federated learning did not show significantly superior results compared to previous models, but there was no substantial difference in the prediction accuracy. In conclusion, federated learning-based prediction models can be utilized appropriately in areas sensitive to privacy without requiring relatively high predictive accuracy, such as a driver's preferred route choice.