• 융복합기술연구소 논문집
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• 제6권1호
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• pp.13-16
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• 2016

The purpose of this study is analysing the characteristics of vehicle fuel economy and greenhouse gase emissions according to driving pattern of drivers. Current fuel economy has not established on official test methods. The difference between actual fuel efficiency and specification fuel efficiency bring up consumer complaints and misunderstandings about fuel economy. Against this background, The country is progressing the study on influence of the fuel efficiency according to variety test conditions. This study analyze the driving pattern of the different drivers and influence of the fuel efficiency according to driving pattern of different drivers.

• 대한교통학회지
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• 제28권3호
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• pp.109-117
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• 2010

첨단교통정보제공시스템(ATIS)분야는 실시간 교통정보를 가변전광표지(VMS), 인터넷, 교통방송 및 휴대폰 등 다양한 정보제공매체를 통해 제공함으로써 주어진 교통자원을 효율적으로 활용하여 도로 이용자들이 목적지까지의 통행함에 있어 시간 및 비용을 절감시킬 수 있도록 함에 그 목적이 있다. 이러한 교통정보는 시간적 경제적인 면뿐만 아니라 이용자의 심리나 정서적인 부분, 즉 교통정보를 제공받음으로 인한 불안감 해소와 같은 심리적인 부분에서도 상당한 편익을 제공할 수 있는 가치를 지니고 있다. 본 연구에서는 이러한 도로 이용자들이 느끼는 교통정보의 효용성을 평가하고 이용자가 느끼는 만족의 정도에 미치는 요인을 분석하고자, 다양한 교통정보 제공 매체별 이용자 만족도 모형을 구축하고자 하였다. 모형 구축 결과, 각 매체별로 만족도에 영향을 미치는 요인과 그 영향정도가 조금씩 다르나, 공통적인 영향요인으로 운전자들이 교통정보를 보고 그로 인한 심리적인 안정감이나 경로선택 및 변경에 도움이 있었는지에 여부를 나타내는 효율성이 만족도에 가장 큰 영향을 미치고 있음을 분석할 수 있었다.

• 보건행정학회지
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• 제10권4호
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• pp.116-143
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• 2000

Considerable attention has been devoted in the accounting literature to identify the factors that cause or drive the costs of overhead activities. This paper extends recent cost driver research to the health care provider. In various case studies, it has been suggested that overhead costs are driven by volume and complexity variables. This paper investigates the significance of these variables in determining hospital overhead costs, how they are structurally related and how the cost impacts of these variables can be estimated in practice. This paper analyzes the determinants of hospital costs using the sample of South Korea hospitals for seven year during the period 1952－1997. The paper focuses on the extent to which hospital overhead costs depend on complexity, efficiency in addition to depending on more conventional volume based measures of hospital activity. The results of regression analysis suggest that volume and complexity factors positively and significantly affect overhead costs in the hospital industry. The results show that the complexity-related cost drivers strongly affected on the overhead costs in tile health care provider industry more than manufacturing industry which is mainly affected by volume-related cost drivers. That means each Industry may have different cost structures. Therefore it Is Important to find their proper cost structures and cost drivers and use them. Futhermore identification of overhead or indirect cost drivers is likely to be particularly useful in heath care. The identification of cost drivers can be of benefit to all health care stakeholders because these facilitates more efficient management of the national resources devoted to health care. While this study has documented that the level of service complexity is a significant determinant of hospital overhead costs, caution should be exercised in interpreting this as supportive of the cost accounting procedures associated with ABC. It is an open question whether even a well-designed ABC system will provide suitable proxies for marginal costs for decision making purposes.

• 경영과학
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• 제31권4호
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• pp.135-150
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• 2014

This paper analyzes the operational efficiency of 91 individual retail stores in Seoul by a two-step procedure. In the first step, a data envelopment analysis (DEA) model is used to identify the efficiency scores. Three inputs (store size, number of items, and number of employees) and two outputs (sales and number of customers) are used for the efficiency measurement. In the second step, a Tobit regression model is used to identify the drivers of efficiency. DEA efficiency scores are used to test hypotheses on the impact of five independent variables, namely store age, number of items per store size, number of items per employee, trade area index, and number of competitors. Results of the Tobit analysis show that number of items per store size, number of items per employee, and number of competitors play a significant role in influencing the operational efficiency of retail stores. Managerial implications of the study are discussed.

• 지능정보연구
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• 제10권2호
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• pp.189-209
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• 2004

수요사슬에서 기업간 협업은 통합 (Integration), 협업(Exchange), 그리고 동기화(Syncronize)라는 3 단계의 계층구조를 갖으며, 단계가 높을수록 협업의 지능성은 강하다. 이 논문은 국내의 제조업과 서비스업을 중심으로 지능적인 수요사슬 통합전략(공급통합, 수요통합, 수요사슬통합)을 수행하는데 영향을 주는 동인들을 발견한다. 여기 동인에는 효율적 동인과 시대적 동인으로 구분하여 각 통합전략에 어떻게 영향을 미치는 지를 조사하여, 그 특징을 파악하고 문제점을 제시한다. 인터넷 강국인 국내기업의 통합전략과 동인에 대한 면밀한 분석을 통해 기업에게 가장 이상적인 통합전략이 무엇인지를 제시한다. 결론에서는 고객과 통합을 추진하는 통합전략을 선택한 기업은 웹통합을 하는 가장 큰 이유는 경영성과를 높이기 위해 추진하는 것으로 나타났으며, 공급자와 통합을 하는 전략을 선택한 기업은 외부환경의 압력에 의해서 어쩔 수 없이 추진하는 것으로 해석된다.

• 대한인간공학회지
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• 제22권2호
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• pp.15-28
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• 2003

The one of the most important factors is the platoon design on developing AH3(Advanced Highway System), as it is related to traffic efficiency and drivers' safety. This study was evaluated that how much speed is comfortable for drivers and how long distance is appropriate for vehicular gap of platoon by measuring drivers' physiology signal and sensibility. A fixed-based AHS simulator was developed by using a real vehicle cockpit and the restructured part of Korean highway for human factors evaluation. The EEG(electroencephalogram), ECG (electrocardiogram) and GSR(Galvanic Skin Response) were measured for obtaining drivers' physiology signal according to the change of speed and gap. The brain wave(${\alpha},\;{\beta},\;{\delta},\;{\theta}$) by EEG, the response of the autonomic nervous system. the sympathetic and parasympathetic nervous system, by ECG, and relax-arousal situation by GSR were analyzed. The SD(Semantic Differential) method was also applied to evaluate drivers' sensibility by 5-grade evaluation scale with 96 adjectives. SSQ(Simulator Sickness Questionnaire) was used to measure the simulator sickness of pre and post driving, two times. As the results, drivers were comfortable with 120km/h speed of platoon and lam to 15m vehicular distance. The results of this study may differ from the adaption of the reality because of many parameters. However, the purpose of this study is show to significant results of the drivers' safety and the acceptability of human factors evaluation.

• Journal of Power Electronics
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• 제6권1호
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• pp.73-82
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• 2006

Plasma display panels (PDPs) have a serious thermal problem, because the luminance efficiency of a conventional PDP is about 1.5 1m/W and it is less than $3\~5\;lm/W$ of a cathode ray tube (CRT). Thus there is a need for improving the luminance efficiency of the PDP. There are several approaches to improve the luminance efficiency of the PDP and we adopted a driving PDP at high frequency range from 400kHz up to over 700kHz. Since a PDP is regarded as an equivalent inherent capacitance, many types of sustaining drivers have been proposed and widely used to recover the energy stored in the PDP. However, these circuits have some drawbacks for driving PDPs at high frequency ranges. In this paper, we investigate the effect of the parasitic components on the PDP itself and on the driver when the reactive energy of the panel is recovered. Various drivers are classified and evaluated based on their suitability for high frequency drivers. Finally, a current-fed driver with a DC input voltage bias is proposed. This driver overcomes the effect of parasitic components in the panel and driver. It fully achieves a ZVS of all full-bridge switches and reduces the transition time of the panel polarity. It is tested to validate the high frequency sustaining driver and the experimental results are presented.

• 전력전자학회논문지
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• 제18권4호
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• pp.397-402
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• 2013

This paper proposes a new passive type LED driver which satisfies the standard of power factor (PF) and total harmonic distortion (THD). The proposed passive LED driver also has high-efficiency and long-life time characteristics compared to active LED driver which is composed of op-amp, switches and so on. By using just passive components such as inductor, capacitor, and diode, it has resolved extremely short-life time and low-efficiency problems of previous LED drivers. It has achieved PF of 0.99, THD of 16.4 %, and the total efficiency of 95 %. The proposed passive LED driver is fully analyzed and verified by simulations and experiments, which results are in good agreement each other.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1405-1411
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• 2011

It is very often for the experienced diesel locomotive drivers to identify the proper replacing time for the fuel adjustment tube only based on their experience. Because of that, sometimes the locomotive's fuel is burned out due to the unnecessary torque. Or sometimes, the locomotive does not operate with its accelerating performance because the fuel is not supplied at the appropriate moment. Meanwhile, recent typical auto vehicles provide drivers with the average fuel efficiency and the instant fuel efficiency in real-time. By providing the real time display mentioned above, it is one of the good examples that those drivers, who had driven their cars not properly and used a lot of fuel with their bad driving habits, obtain the efficient driving pattern by continuous educating effect. Similarly, if the diesel locomotive provides the train driver with the optimal driving pattern within a certain driving section, it will be effective for fuel saving. It is possible to make the most effective driving pattern by performing the repeated trial running especially for the railway because the track's operating routes, its grades, and etc are relatively precise. This research analyzes the result data which was obtained by many times trial running on the identical section after equipping the fuel use measuring device to a certain test vehicle, and confirms the fuel saving effect depending on the driving pattern along the test section. At the same time, the research to establish the optimal driving pattern was progressed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.380-384
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• 2005

Plasma display panel (PDP) has a serious thermal problem, because the luminance efficiency of the conventional PDP is about 1.5 lm/W and it is less than $3{\sim}5$ lm/W of cathode ray tube (CRT). Thus there is a need for improving the luminance efficiency of the PDP There are several approaches to improve the luminance efficiency of the PDP and we adopt the driving PDP at high frequency range from 400 kHz up to over 700 kHz. Since a PDP is regarded as an equivalent inherent capacitance, many types of sustaining drivers have been proposed and widely used to recover the energy stored in the PDP. However, these circuits have some drawbacks for driving PDP at high frequency range. In this paper, we investigate the effect of the parasitic components of PDP itself and driver when the reactive energy of panel is recovered. Various drivers are classified and evaluated whether it is suitable for high frequency driver, and finally current-fed type with do input voltage biased is proposed. This driver overcomes the effect of parasitic component in panel and driver and fully achieves ZVS of all full-bridge switches and reduces the transition time of the panel polarity.