• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.71-78
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• 2005

This paper proposes a novel multi-level energy recovery sustaining driver for AC PDP(Plasma Display Panel), which solves the problems of the conventional multi-level sustaining driver. While the conventional circuit improves the voltage md current stress of the switching elements in Weber circuit not only there are parasitic resonant currents between resonant inductors and parasitic capacitance and hard switching, but also the changing period between 0 and sustain voltage is too long. Comparing the proposed circuit with the conventional circuit, the number of components are reduced and the parasitic resonant currents in resonant inductors are eliminated Moreover the hard switching problem is solved by using CIM(Current Injection Method) and the operating frequency will be high as much as possible by removing Vs/2 sustain period. And the circuit operations of the proposed circuit are analyzed for each mode and the validity is verified by the simulations using PSpice program.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.481-484
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• 2011

Recent Automotive technology is driven from mechanical device to the electronic components which improve the vehicle's safety and convenience. The future competitiveness of the car will come from safety issues and energy efficiency, convenience and the application of the technologies. In this study, various techniques for driver drowsiness detection are introduced and compared with each others. The advantages and disadvantages of commercially available technologies and developed technologies are compared. To enhance the detection resolution, multiple sensing technologies are introduced in this paper. The feasibility of two drowsiness detection methods, that is, existing camera image recognition method and bio signal analysis method, are tested. The direct drowsiness detection by the camera image of eyes and driver's vital signs detected indirectly are combined and analyzed by the developed noble algorithm for stress, fatigue, drowsiness detection with a more accurate high-drowsiness detection.

• Korean Journal of Culture and Social Issue
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• v.22 no.2
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• pp.285-311
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• 2016

This study analysed the published papers dealing with traffic behaviors since 2004 in south Korea. The following information was coded for each papers; year of publication, source, authors, main topic, and subtopic. The annual numbers of publication in 2004 and 2005 showed 6 articles and 7 articles. Since 2006, The annual numbers were increasing more than 10 papers. It means that the researches on traffic behavior were rich. The driver was main topic of 73.2% of articles. Cognition & Perception, Fatigue and Stress, and Alcohol were the main interest sub-topics dealing with main topic driver. Elderly driver was 10.4%, the interest in elderly drivers grew with population aging. And the dominant publications were Journal of traffic safety research, Journal of Korean Psychology Association, and Journal of the Koean Data Analysis Society with 60% of all articles for last 10 years.

• Journal of Power Electronics
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• v.4 no.1
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• pp.39-45
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• 2004

A novel current-fed energy-recovery sustaining driver (CFERSD) for a PDP is proposed in this paper. Its main idea is to recover the energy stored in the PDP or to inject the input source energy to the PDP by using the current source built-up in the energy recovery inductor. This method provides zero-voltage-switching (ZVS) of all main power switches, the reduction of EMI, and more improved operational voltage margins with the aid of the discharge current compensation. In addition, since the current flowing through the energy recovery inductor can compensate the plasma discharge current flowing through the conducting power switches, the current stress through all main power switches can be considerably reduced. Furthermore, it features a low conduction loss and fast transient time. Operations, features and design considerations are presented and verified experimentally on a 1020${\times}$l06mm sized PDP, 50kHz-switching frequency, and sustaining voltage 140V based prototype.

• Tribology and Lubricants
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• v.31 no.1
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• pp.13-20
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• 2015

The impact beam, a beam-shaped reinforcement installed horizontally between the inside and outside panels of car doors, is gaining importance as a solution to meet the regulations on side collision of vehicles. In order to minimize pelvis injury which is the biggest injury happening to the driver and passengers when a vehicle is subject to side collision, energy absorption at the door impact beam should be maximized. For the inner panel, the thrust into the inside of the vehicle must be minimized. The impact beam should be as light as possible so that the extent of pelvis injury to the driver and passenger during side collision of the vehicle is minimal. To achieve this, the weight of the impact beam, has to be optimized. In this study, we perform a design analysis with a goal to reduce the weight of the current impact design by 30% while ensuring stability, reliability, and comparison data of the impact beam for mass production. We conduct three-point bending stress experiments on conventional impact beams and analyze the results. In addition, we use a side-door collision test apparatus to test the performance of beams made of three (different materials: steel, aluminum, and composite beams).

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1251-1254
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• 2006

A novel a-Si TFT integrated gate driver circuit using multi-thread driving has been developed. The circuit consists of two independent shift registers alternating between the two mode, "wake" and "sleep". The degradation of the circuit is retarded since the bias stress is removed during the sleep mode. It has been successfully integrated in 14.1-in. XGA LCD Panel, showing enhanced stability.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.944-947
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• 2005

Highly stable gate driver circuit using a-Si TFT has been developed. The circuit has dual-pull down structure, in which bias stress to the TFTs is relieved by alternating applied voltage. The circuit has been successfully integrated in 4-in. QVGA and 14-in. XGA TFT-LCD with a normal a-Si process, which are stable for over 2,000 hours at $60^{\circ}C$. The enhancement of stability of the circuit is attributed to retarded degradation of pull-down TFTs by AC driving.

• Journal of Power Electronics
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• v.11 no.1
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• pp.97-104
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• 2011

This paper proposes a new alternating current driving method for highly capacitive loads such as plasma display panels or piezoelectric actuators, etc. In the proposed scheme, a current balance transformer, which has two windings with the same turn-ratio, provides not only a resonance inductance for energy recovery but also a current balance among all of the switching devices of the driver for current stress reduction. The smaller conduction loss than conventional circuits occurs due to the dual conduction paths which are parallel each other in the current balance transformer. Also, the leakage inductances of the transformer are utilized as resonant inductors for energy recovery by the series resonance to the capacitive load. Furthermore, the resonance contributes to the small switching losses of the switching devices by soft-switching operation. To confirm the validity of the proposed circuit, prototype hardware with a 12-inch mercury-free flat fluorescent lamp is implemented. The experimental results are compared with a conventional energy-recovery circuit from the perspective of luminance performances.

• Korean Journal of Occupational Health Nursing
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• v.24 no.4
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• pp.363-371
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• 2015

Purpose: The purpose of this study was to investigate the factors influencing health promoting lifestyle of urban bus driver in small-sized companies. Methods: This study included 118 urban bus drivers who completed questionnaires. The data were collected from 6 small-sized bus companies located in a metropolitan city, from January to February 2015. Analyses were done using descriptive statistics, independent t-test, ANOVA, Pearson's correlation, and multiple regression analysis. SPSS/Win 18.0 was used. Results: The scores of HPLP of urban bus drivers were 2.7 (on a 4-point scale). Mean of HPLP sub-scores were self-fulfillment ($3.0{\pm}0.5$), interpersonal relationship ($2.9{\pm}0.5$), physical activity ($2.9{\pm}0.7$), health responsibility ($2.7{\pm}0.5$), healthy diet ($2.6{\pm}0.6$), and stress management ($2.5{\pm}0.5$). Among independent variables, job satisfaction and presence of religion were significantly related to health promoting lifestyle (explained 39.2%). Conclusions: This study revealed that there is a need to strengthen job satisfaction for urban bus drivers' health promoting lifestyle.

• Asia-Pacific Journal of Business
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• v.14 no.3
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• pp.221-240
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• 2023

Purpose - This paper investigates how business cycle impacts on corporate credit spreads since global financial crisis. Furthermore, it tests how the impact changes by the phase of the cycle. Design/methodology/approach - This study collected dataset from Barclays Global Aggregate Bond Index through the Bloomberg. It conducted multi-regression analysis by projecting business cycle using Hodrick-Prescott filtering and various cyclical variables, while ran dynamic analysis of 5-variable Vector Error Correction Model to confirm the robustness of the test. Findings - First, it proves to be statistically significant that corporate credit spreads have moved countercyclicaly since the crisis. Second, It indicates that the corporate credit spread's countercyclicality to the macroeconomic changes works symmetrically by the phase of the cycle. Third, the VECM supports that business cycle's impact on the spreads maintains more sustainably than other explanatory variable does in the model. Research implications or Originality - It becomes more appealing to accurately measure the real economic impact on corporate credit spreads as the interaction between credit and business cycle deepens. The economic impact on the spreads works symmetrically by boom and bust, which implies that the market stress could impact as another negative driver during the bust. Finally, the business cycle's sustainable impact on the spreads supports the fact that the economic recovery is the key driver for the resilience of credit cycle.