• Journal of Intelligence and Information Systems
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• v.13 no.3
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• pp.101-117
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• 2007

In this paper, we propose a customized genetic algorithm (GA) to find the minimum-cost guideway network (GN) of personal rapid transit (PRT) subject to connectivity, reliability, and traffic capacity constraints. PRT is a novel transportation concept, where a number of automated taxi-sized vehicles run on an elevated GN. One of the most important problems regarding PRT is how to design its GN topology for given station locations and the associated inter-station traffic demands. We model the GN as a directed graph, where its cost, connectivity, reliability, and node traffics are formulated. Based on this formulation, we develop the GA with special genetic operators well suited for the GN design problem. Such operators include steady state selection, repair algorithm, and directed mutation. We perform numerical experiments to determine the adequate GA parameters and compare its performance to other optimization algorithms previously reported. The experimental results verify the effectiveness and efficiency of the proposed approach for the GN design problem having up to 210 links.

• Fashion & Textile Research Journal
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• v.20 no.1
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• pp.63-74
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• 2018

The purpose of this study is to investigate the differences in riding characteristics and helmet wearing conditions between bicycle and PMV riders so that the basis data necessary for the development of suitable helmets for each group is provided. For this purpose, riding characteristics and helmet wearing conditions of bicycle and PMV users were investigated using online survey method and then the survey results were interpreted by in-depth interview conducted for bicycle and PMV users. The online survey results showed that the PMV group showed shorter driving distance and more driving frequency than bicycle group. This short driving distance was due to the limitation of battery capacity of PMVs. Helmet wearing rate was significantly lower in PMV group than in bicycle group, which was associated with relatively low chances to drive long distance on the motorway. In the PMV group, the 'urban helmets' were mainly used, in which the appearance of helmet was priorized, but in the bicycle group, the 'road cycle helmets' were mainly used, in which the light weight or ventilation were priorized. Urban helmets caused stronger pain and more fitting problems than road cycle helmets because the head shapes of Koreans were not properly applied to the helmet design. Since the fitting problem and pain intensity were the important causes that making PMV users not wear the helmets, it is necessary to develop the urban helmets reflecting the head shapes of Koreans in order to increase the helmet wearing rate of the PMV users.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.10
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• pp.781-785
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• 2009

We can constantly gather personal life log from developed mobile device. However, gathered personal life log in mobile environment have a large amount log and uncertainty such as uncertainty of mobile environment, limited capacity and battery of mobile device. Tagging task using a landmark such as a key word should be required to overcome the above problem and to manage personal life log. In this paper, we propose new tagging method and a life log tagging interface using high level context recognizer based on probability. The new tagging method extract high level context such as landmark of life log using recognizer which is modeled from bayesian network and recommend recognized high level context to user using tagging interface. Finally user can directly do tagging task to life log. This task is a special feature in our process. As the result of experiments in task support level which include usability, level of a goal, function and leading, we achieved a feeling of satisfaction of 81%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5855-5877
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• 2017

In view of personal health and disease management based on cost effective healthcare services, there is a growing need for real-time monitoring services. The electrocardiogram (ECG) signal is one of the most important of health information and real-time monitoring of the ECG can provide an efficient way to cope with emergency situations, as well as assist in everyday health care. In this system, it is essential to continuously collect and transmit large amount of ECG data within a given time and provide maximum user convenience at the same time. When considering limited wireless capacity and unstable channel conditions, appropriate signal processing and transmission techniques such as compression are required. However, ISO/IEEE 11073 standards for interoperability between personal health devices cannot properly support compressed data transmission. Therefore, in the present study, the problems for handling compressed data are specified and new extended agent and manager are proposed to address the problems while maintaining compatibility with existing devices. Extended devices have two PM-stores enabling compression and a novel transmission scheme. A variety of compression techniques can be applied; in this paper, discrete cosine transformation (DCT) is used. And the priority of information after DCT compression enables new transmission techniques for performance improvement. The performance of the compressed signal and the original uncompressed signal transmitted over the noisy channel are compared in terms of percent root mean square difference (PRD) using our simulation results. Our transmission scheme shows a better performance and complies with 11073 standards.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.42-54
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• 2008

In recent years, embedded systems have been expanding their application domains from traditional embedded systems such as military weapons, robots, satellites and digital convergence systems such as celluar phones, PMP(Portable Multimedia Player), PDAs(Personal Digital Assistants) to Next Generation Personal Computers(NGPCs) such as eating PCs, wearable computers. The NGPCs are network-based, human-centric digital information devices diverged from the traditional PCs used mainly for document writing, internet searching and database management. Wearable computers with battery capacity and memory size limitations have to use real-time operating systems with small footprints and low power management techniques to provide user's QoS in spite of hardware constraints. In this paper, we have designed and implemented a low-power RTOS (called eRTOS) for wearable computers. The implemented eRTOS has 18KB footprints and the dynamic power management and the device power management schemes are adapted in it. Experimental results with wearable computer applications show that the low power techniques could save energy up to 47 %.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.180-189
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• 2019

The purpose of this study is to analyze the factors that affect the entrepreneurial satisfaction of entrepreneurs, based on the characteristics of entrepreneurial firms. For this purpose, we tried to derive the psychological factors besides the personal characteristics of the entrepreneurs as the factors affecting the entrepreneurial satisfaction, which is the result of much research. Psychological factors were empirically analyzed by satisfaction with job and work environment through entrepreneurship, satisfaction with economic employment stability and income factors, and individual development potential, autonomy, and social reputation. The results of this study are as follows: First, the sample consists of entrepreneurs who have been engaged in entrepreneurship activity in Busan for 3 years. Through technical statistical analysis, correlation analysis and multiple regression analysis, The hypotheses about entrepreneurship satisfaction were verified and meaningful results and implications could be derived. Based on this, it can be extended to include research on firm capacity variables such as financial indicators and technological power that were not reflected in this study in the future.

• Journal of information and communication convergence engineering
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• v.12 no.2
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• pp.109-115
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• 2014

This paper presents a concurrent channel time allocation scheme used in the reservation period for concurrent transmissions in 60-GHz wireless personal area networks (WPANs). To this end, the proposed resource allocation scheme includes an efficient method for creating a concurrent transmission group by using a table that indicates whether individual streams experience interference from other streams or not. The coordinator device calculates the number of streams that can be concurrently transmitted with each stream and groups them together on the basis of the calculation result. Then, the coordinator device allocates resources to each group such that the streams belonging to the same group can transmit data concurrently. Therefore, when the piconet coordinator (PNC) allocates the channel time to the individual groups, it should allow for maximizing the overall capacity. The performance evaluation result demonstrates that the proposed scheme outperforms the random grouping scheme in terms of the overall capacity when the beamwidth is $30^{\circ}C$ and the radiation efficiency is 0.9.

• Journal of Preventive Medicine and Public Health
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• v.23 no.2 s.30
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• pp.216-223
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• 1990

To identify the factors influencing the charges per case of acute appendicitis and normal spontaneous vaginal delivery (NSVD), the personal data-base files and hospital-characteristics-reporting data files of Korea Medical Insurance Corporation were analyzed. One hundred and twenty-nine institutions were selected. The results of this study were as follows 1. The differences of charges per case with respect to hospital ownership, location, and equipment levels were statistically significant. 2. The results of multiple regression analysis revealed that bed capacity was the most significant variable in both diseases. 3. Ownership was significant variable in acute appendicitis. In NSVD, ownership and hospital equipment level were statistically significant. In conclusion, bed capacity was statistically the most significant variable in the analysis of charages per case. And we thought that the results of this study would influence the policy of the hospital bed supply.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.543-553
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• 2020

The purpose of this study is to investigate factors affecting the leadership capacity of middle managers and then evaluate the corresponding effect on the performance of subordinates in Vietnamese economic and defense enterprises. Data for the study was collected from questionnaire survey of 15 economic and defense enterprises, preceded by in-depth interviews with respondents who are subordinates of the departments/divisions of these enterprises. The research used logistic regression estimator to address econometric issues and to improve the accuracy of the regression coefficients. Our results show that the determinants of the leadership capacity of mid-level managers in defense and economic enterprises include: (i) personal qualities and qualities of managerial officials (understanding, courage), fairness, assertiveness and compliance), and leadership behaviors of two leadership styles - (ii) a transforming leadership style (influenced by ideals, inspirations, concerns) subordinates, stimulating intellect) and (iii) transactional leadership style (rewarding, detecting and handling problems for subordinates). Based on these results, our study suggests that middle managers should possess superior knowledge, care more about subordinates, understand the strengths and weaknesses of each subordinate, always be creative, assertive and courageous people as well as have high standards of competency and morality in order to become outstanding leaders in Vietnamese economic and defense enterprises.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.327-332
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• 2019

Recently, inverter control systems have attracted immense attention to increase the energy efficiency. However, such systems use repeated on/off high currents for linear operation control, instead of the prevalent step variable current control method. Hence, there arise concerns of personal and property damage, especially due to the durability, explosive characteristics, and operating speed of the fuse, which is responsible for safety and is one of the internal components using current control. Therefore, in this paper, we propose an IEC60127-4 SMD sub-miniature fuse, consisting of Ag-Cu alloys and ceramic powder for arc soothing. The IEC60127-4 SMD sub-miniature fuse has high durability and cut-off capacity, and operates safely in dangerous circumstances caused by the inverter control system.