• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.44 no.2
• /
• pp.1-14
• /
• 2021

It is highly challenging to measure the efficiency of electric vehicle charging stations (EVCSs) because factors affecting operational characteristics of EVCSs are time-varying in practice. For the efficiency measurement, environmental factors around the EVCSs can be considered because such factors affect charging behaviors of electric vehicle drivers, resulting in variations of accessibility and attractiveness for the EVCSs. Considering dynamics of the factors, this paper examines the technical efficiency of 622 electric vehicle charging stations in Seoul using data envelopment analysis (DEA). The DEA is formulated as a multi-period output-oriented constant return to scale model. Five inputs including floating population, number of nearby EVCSs, average distance of nearby EVCSs, traffic volume and traffic congestion are considered and the charging frequency of EVCSs is used as the output. The result of efficiency measurement shows that not many EVCSs has most of charging demand at certain periods of time, while the others are facing with anemic charging demand. Tobit regression analyses show that the traffic congestion negatively affects the efficiency of EVCSs, while the traffic volume and the number of nearby EVCSs are positive factors improving the efficiency around EVCSs. We draw some notable characteristics of efficient EVCSs by comparing means of the inputs related to the groups classified by K-means clustering algorithm. This analysis presents that efficient EVCSs can be generally characterized with the high number of nearby EVCSs and low level of the traffic congestion.

• Annals of Clinical Neurophysiology
• /
• v.10 no.1
• /
• pp.29-32
• /
• 2008

Although various criteria on the diagnosis of diabetic neuropathy are applied from trial to trial, being tailored in concert with its purpose, the utmost evidences of the diagnosis are subjective symptoms and objective signs of neurologic deficit. The application and interpretation of auxiliary electrophysiological test including nerve conduction study (NCS) should be made on the context of clinical pictures. The evaluation of the functions of small, thinly myelinated or unmyelinated nerve fibers has been increasingly stressed recently with the advent of newer techniques, e.g., measurement of intraepidermal fiber density, quantitative sensory testing, and autonomic function test. And the studies with those techniques have shed light to the nature of the evolution of diabetic neuropathy. The practical application of these techniques to the diagnosis of diabetic neuropathy in the individual patients, however, should be made cautiously due to several shortcomings: limited accessibility, wide overlapping zone between norm and abnormality with resultant unsatisfactory sensitivity and specificity, difficulty in performing subsequent tests, unproven quantitative correlation with clinical deficit, and invasiveness of some technique. NCS, as an extension of clinical examination, is still the most reliable electrophysiological test in evaluating neuropathy and gives the invaluable information about the nature of neuropathy, whereas the newer techniques need more refinement of the procedure and interpretation, and the accumulation of large scaled data of application to be considered as established diagnostic tools of peripheral neuropathy.

• Korean Journal of Agricultural Science
• /
• v.37 no.1
• /
• pp.37-43
• /
• 2010

This study carried out to develop barrier-free certification program in forest trail. It is done to provide the certification system presented about certification organized, certification standard and indexes, evaluation method and operation plan. In order to develop certification program in forest trail, detailed measurement index must be developed earlier based on an accessbility, a stability, a preservation and a walking continuity. The suitable forest trail for weak pedestrian was investigated that running slope should be 1/20(5%) maximum, cross slope cannot exceed 1/50(2%) maximum and clear tread width should be above of minimum 90cm. In addition, the trail type is designed as a mixed trail system which is a combination of the loop and the line form and its distance should be 225~675m. Finally, forest trail should be manage sustainably by having regular monitoring and evaluation.

• Korean Journal of Health Education and Promotion
• /
• v.20 no.3
• /
• pp.171-188
• /
• 2003

This study, based on stages of behavioral change, was aimed at suggesting strategies for the adoption of moderate drinking habits for community-based health education designed to help rural people. An interview survey was conducted during the period from March 4 to April 5, 2002 by sampling 467 rural people living in 6 villages covered by a public healthcare clinic. The results of this study can be summarized as follows； 1. The perceived non-moderate drinkers were less prepared for behavioral change. 2. The heavier drinking habits were ‘drinking alone’, ‘meals accompanied by drinking’ and ‘drinking twice or more at a time’. The agricultural off-season and the custom of brewing liquor at home were negative environmental factors for moderate drinking. 3. The predisposing factors affecting moderate drinking were recognition of health, expectation of the drinking effect, etiquette encouraging overdrinking and control of drinking. The reinforcing factors were stress from ordinary life and perception of being loved. The enabling factor was accessibility to the public healthcare clinic. 4. Rural residents are less motivated to participate in health education for moderate drinking. Based on the above findings, health education strategies for each stage can be suggested as follows： 1) Pre-contemplation stage： improvement of perception, motivation, sharing of experiences, and reawakening. 2) Contemplation/preparation stag e： measurement of value, departure from the inertia against a change, formation of a habit, and reinforcement of the behavior. 3) Action/maintenance stage： creation of a social atmosphere, encouragement of participation, change of life style, and improvement of environment.

• Transactions of the Korean hydrogen and new energy society
• /
• v.20 no.2
• /
• pp.125-132
• /
• 2009

Cylinder shaped air-breathing PEMFC has been developed to have small volume, low contact resistance and better air accessibility to the open cathode. This cylinder shaped design consists of an anode cylinder with helical flow channel and a cathode current collector with slits. The pressure distribution measurement according to the shapes was performed. The test result indicated that cylinder shaped fuel cell has better pressure distribution compared with the planar shaped fuel cell. The better pressure distribution was connected to the higher performance. The maximum power density of cylinder shaped fuel cell was about 20% higher than the planar shaped fuel cell. The maximum power density of the developed cylinder shaped air-breathing PEMFC with dry hydrogen was $220\;mW/cm^2$ and with humidified hydrogen was $293\;mW/cm^2$.

• Journal of Environmental Science International
• /
• v.18 no.10
• /
• pp.1079-1088
• /
• 2009

The statistics of monitoring on soil quality is a report statistics which is made on the basis of Article 15, Environment Strategy Basic Law and Article 5, Soil Environment Conservation Law. This study was conducted according to quality assessment of Korea National Statistical Office. The assessment of quality infrastructure advised that the authority bring up and increase completely responsible officer and secure the budget. The assessment of user satisfaction and reflection of request propose that the statistics is focused on soil background concentration, decrease soil sampling points and extend survey period. The assessment of error management system per processes of detailed preparation suggest change of the statistics objective, a reduction of sampling points and improvement of survey period and soil measurement properties. Accuracy assessment of data proposed cuts of sampling points, accessibility increment and build up of management system linking subordinates and Ministry of Environment. The substantiality assessment of data service demonstrated information environment improvement for users including reference expression and records of statistics table and figure contents.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.32 no.12
• /
• pp.1088-1095
• /
• 2008

5-axis NC machining has a good advantage of the accessibility of tool motion by adding two rotary axes. It offers numerous advantages such as expanding machining fields in parts of turbo machineries like impeller, propeller, turbine blade and rotor, reasonable tool employment and great reduction of the set-up process. However, as adding two rotary axes, it is difficult to choose suitable machining conditions in terms of tool path, tool posture, feedrate control at a tool tip and post-processing. Therefore in this paper, it is proposed to decide suitable machining condition through an experimental method such as adopting various tool paths, tool postures, and feedrate types. Machining experiment on AL7075 for impeller is performed to define suitable machining condition, and measurement of surface roughness on machined surfaces depended on each machining condition is performed. By defining suitable machining condition, we should have conclusion as improving the surface quality in the aspect of surface roughness and machined shape of surface.

• Journal of Preventive Medicine and Public Health
• /
• v.42 no.3
• /
• pp.151-159
• /
• 2009

Objectives : This study was to determine how the perception and the satisfaction of outpatients who utilized clinics and hospitals are structurally related with their willingness to utilize the same institution in the future. Methods : Three hundred and ten responses (via convenient sampling) were collected from 5 hospitals and 20 clinics located in Seoul listed in the "Korea National Hospital Directory 2005". Service quality was utilized as the satisfaction measurement tool. For analysis, we used a structural equation modeling method. Results : The determining factors for general satisfaction with medical services are as follows: medical staff, reasonability of payment, comfort and accessibility. Such results may involve increased competition in the medical market and increased demands for quality medical services, which drive the patients to visit hospitals on their own on the basis of changed determining factors for satisfaction. Conclusions : The structural equation model showed that the satisfaction of outpatients with the quality of medical services is influenced by a few sub-dimensional satisfaction factors. Among these sub-dimensional satisfaction factors, the satisfaction with medical staff and payment were determined to exert a significant effect on overall satisfaction with the quality of medical services. The structural relationship in which overall satisfaction perceived by patients significantly influences their willingness to use the same institution in the future was also verified.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.813-816
• /
• 2013

National Radio Research Agency(RRA) has legislated technical regulations of telecommunication equipments. These technical regulations are related to safety of operators and users, service quality, accessibility for the disabled, interoperability and network connection of terminal equipment. Also, RRA drives the establishment or amendment of technical regulations for terminal equipment considering the evolution of ICT technicology and diversification of services. In 2013, RRA researched the amendment of technical regulations in relation to terminal equipment, which are related to the measurement frequency for signal band power, unwanted signal power, pulse shape.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.64
• /
• pp.187-210
• /
• 2014

As port functions change to act as an economic catalyst and take on a central position in industries engaged in international trade, port hinterland has become a significant component in international shipping. The success of port hinterland as a strategic base of logistic activities critically depends on location selection factor for international distribution center that links elements of global supply chain management. By examining multi-measurement items empirically, this paper analyzed location selection factor for international logistics distribution center in port hinterland, and evaluated Busan new port hinterland from the user's perspective. Employing exploratory factor analysis, the results revealed that the model structured around five factors incorporating geo-location and accessibility, availability, political supports, cost factors, and quality of business environment is valid and reliable in the context of the location selection factors for logistics distribution center in the context of port hinterland operations. The evaluation of Busan new port hinterland provides useful insights for strategic improvement to accommodate the users' expectation. Further, the model offers both a descriptive and diagnostic strategic management tool for port hinterland development and operations, to guide future improvement.