• Laser Solutions
• /
• v.10 no.1
• /
• pp.11-17
• /
• 2007

We presented the proper laser processing conditions for the capillary line marking, which could be applied for the fabrication of injection needles. With changing the parameters such as lamp current, duty cycle and beam amplification factor of beam expander, we evaluated the processing performance considering amount of dross, processing efficiency and processed linewidth in the sample. We could carry out the proper line marking at the condition of 70% lamp current, duty cycle of 7-10% and 6-times amplification of beam diameter. To perform efficient line processing, the utilization of duty cycle of 12% at 80% lamp current was also preferred.

• Proceedings of the KIPE Conference
• /
• 2006.06a
• /
• pp.254-256
• /
• 2006

A Novel way to support typical Thermal Shut Down(TSD) circuit is proposed. In power ICs, on-time or on-duration is the key factor to anticipate an abrupt increase of internal temperature. Such an abrupt raise of the temperature can cause TSD circuit cannot protect on proper time due to the temperature detection delay come from the physical distance or the imperfect coupling between heat sources and detector. The proposed circuit checks the duty ratio touched their maximum or not in every cycle. Once duty ratio touches the maximum duty, new circuit generates the warning signal to the TSD circuit and lowers pre-determined temperature for shut down to compensate the detection delay. The novel circuit will be analyzed to the transistor level and checked the validity by simulation.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.13 no.2
• /
• pp.139-144
• /
• 2013

Negative bias temperature instability (NBTI) has become a major factor determining circuit reliability. The effect of the NBTI on the circuit performance depends on the duty cycle which represents the stress and recovery conditions of each device in a circuit. In this paper, we propose an analytical model to perform more accurate duty cycle estimation at the gate-level. The proposed model allows accurate (average error rate: 3%) computation of the duty cycle without the need for expensive transistor-level simulations Furthermore, our model estimates the waveforms at each node, allowing various aging effects to be applied for a reliable gate-level circuit aging analysis framework.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.10
• /
• pp.1432-1441
• /
• 2012

In this study, an improved LCCT(Inductor-Capacitor-Capacitor-Trans) Z-source inverter(Improved LCCT ZSI) with characteristics of Quasi Z-source inverter(QZSI) and LCCT Z-source inverter(LCCT ZSI) is proposed. The proposed inverter can also reduce the voltage stress and input current/capacitor voltage ripples compared with conventional LCCT ZSI and Quasi ZSI. A two winding trans in Z-impedance network of the conventional LCCT ZSI is replaced by a three winding trans in the proposed inverter. To verify the validity of the proposed inverter, a DSP controlled hardware was made and PSIM simulation was executed for each method. Comparing the current and voltage ripples of each method under the condition of input DC voltage 70[V] and output AC voltage 76[Vrms], the input current and capacitor voltage ripple factors of the proposed inverter were low as 11[%] and 1.4[%] respectively. And, for generation of the same output AC voltage of each method, voltage stress of the proposed inverter was low as 175[V] under the condition of duty ratio D=0.15. As mentioned above, we could know that the proposed inverter have the characteristics of low voltage stress, low ripple factor and low operation duty ratio compared with the conventional methods. Finally, the efficiency according to load change/duty ratio and the transient state characteristics were discussed.

• Journal of Korean Academy of Nursing
• /
• v.40 no.1
• /
• pp.43-51
• /
• 2010

Purpose: The purpose of this study was to investigate sleep habits, sleep disturbance, and circadian types, and to identify factors influencing sleep disturbance in nursing students. Methods: Participants were 140 senior nursing students. The data were collected from May 19 to 27, 2008 using self-report questionnaires. Results: 1) Evening type delayed sleep-wake schedules were more frequent than for morning type, especially during weekend and evening shift duty. 2) In total sleep time, there were no significant statistical differences between morning type and evening type during weekdays, weekend, day or evening shift duty. 3) On weekdays and day shift duty, the mean score for sleep disturbance was significantly higher in the evening type compared to the morning type. 4) Sleep disturbance in weekday and day shift duty was influenced by circadian types, eating habits, and gender. Conclusion: The circadian types are a very important factor for determining the sleep quantity and quality in nursing students.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.1
• /
• pp.59-65
• /
• 2004

The configuration of intake port and piston is a dominant factor of inlet air flow and mixture formation in an engine cylinder, resepectively. This study has analyzed intake port and piston characteristics for swirl flow of a heavy-duty LPG engine. As an available technology to optimize intake port, the steady flow rig test has been applied for measuring swirl ratio and mean flow coefficient. And we measured the mean velocity and turbulence intensity of swirl flow under motoring condition in transparent engine cylinder by backward scattering LDV system. From these results, the piston and cylinder head with a good evaluated swirl flow characteristics were developed and adapted fur a 11L heavy-duty engine using the liquid phase LPG injection (LPLI) system. The obtained results are expected to be a fundamental data for developing intake port and piston.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2008.05a
• /
• pp.407-410
• /
• 2008

This paper presents a maximum power point tracking(MPPT) of photovoltaic system with duty ratio of DC-DC converter considered load. A variation of solar irradiation is most important factor in the MPPT of PV system That is nonlinear, aperiodic and complicated. NN was widely used due to easily solving a complex math problem. The paper consists of solar radiation source, DC-DC converter, DC motor and load(cf, pump). NN algorithm apply to DC-DC converter through an adaptive control of neural network, calculates converter-duty ratio using an adaptive control of NN. The results of an adaptive control of NN compared with the results of converter-duty ratio which are calculated mathematical modeling and evaluate the proposed algorithm. The experimental data show that an adequacy of the algorithm was established through the compared data.

• Fashion & Textile Research Journal
• /
• v.13 no.4
• /
• pp.572-581
• /
• 2011

The purpose of this study was to investigate the effect of duty free shop consumers' store benefits sought and fashion merchandise shopping orientation on store satisfaction. Survey data were collected from questionnaires filled out by 194 domestic consumers who had purchase experience of fashion goods in duty free shops located in Korea. The data were analyzed by reliability analysis, factor analysis, and multiple regression analysis. The results of this study were as follows: First, the store benefits sought was categorized into five factors such as pursuit of convenience, salesperson/atmosphere, promotion, product quality, and product fashionability/variety. The fashion merchandise shopping orientation was categorized into six factors such as pleasure orientation, pursuit of fashion, pursuit of brand, planned orientation, pursuit of confidence, and convenience orientation. The store satisfaction was categorized into six factors such as atmosphere/reputation of store, promotion, product fashionability/variety, convenience, price, and salesperson. Second, the store benefits sought, composed of pursuit of convenience, salesperson/atmosphere, promotion, product quality, and product fashionability/variety, had an effect on the store satisfaction. Third, the shopping orientation such as pleasure orientation, pursuit of fashion, pursuit of brand, and planned orientation, with the exception of pursuit of confidence and convenience orientation, had an effect on the store satisfaction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.4
• /
• pp.57-66
• /
• 2012

When typical Z-source DC/AC inverter(ZSI) is operated in high voltage gain area, because of its high duty ratio, voltage and current stress in Z-network of typical ZSI are increased. This paper proposes a new switched trans ZSI(STZSI) with two switched trans cells which consist of one trans and two diodes. To confirm the operation performance of the proposed system, the PSIM simulation is performed for typical ZSI, switched inductor ZSI and the proposed STZSI. Voltage / current stress and transient state characteristics of each method are compared under the condition of DC input voltage 100[V] and output phase voltage 66[Vrms]. As a result, we confirmed that transient state of the proposed STZSI is short compared with the conventional ZSI because the high voltage gain is obtained using the same duty ratio, also a low duty ratio is required for the same output voltage. Finally, we could know the proposed system have low voltage and current stress in Z-network compared with the conventional ZSI.

• Journal of Nutrition and Health
• /
• v.29 no.6
• /
• pp.651-660
• /
• 1996

The purpose of this study was to examine and analyze the degrees and the influence factors of job satisfaction of dietitians working in hospitals in relation to performance of duty in their works and to provide effective management of hospital dietitians for high quality health and food service in hospital. The questionaire was prepared with reference to the previous studies on job satisfaction of dietitians working in hospitals throughout the nation. 201 dietitians in the country were surveyed. The period of research was from January 20 to February 28, 1995. The results are as follows. 1) In regard to the degree of job satisfaction of hospital dietitians, they showed the highest degree of job satisfaction in the relationships with fellow dietitians followed by worth and self-confidence, aptitude and interests, relationships with cooks, job stability, degree of recognition of the dietitians competence, supervision of the superiors, degree of application of professional knowledge, work load, wage level, degree of recognition of the importance of duty, cooperative relationships with load, wage level, degree of recognition of the importance of duty, cooperative relationships with doctors, degree of performance of clinical work, the number of dietitians, the prromotion system, and welfare system in that order. On the other hand, they showed the highest dissatisfaction with food service facilities. 2) The influence factors on job satisfaction are as follows. (1) Wage factor : Shorter weekday working hours and higher bonuses make greaster job satisfaction (R2=0.3115). (2) Working condition factor : Larger number of monthly holidays(R2=0.5142), shorter weekday working hours(R2=0.1077), longer previous food service experience and computer utilization (R2=0.1432) make greater job satisfaction. (3) Welfare factor : Welfare system (R2=0.4132) and promotion system (R2=0.1624) have to do with computer utilization. Job stability has to do with marital status and computer utilization (R2=0.1165). consequently, those married dietitians who use computers show higher job satisfaction. (4) Human relationship factor : Smaller mumber of patients receiving food makes greater job satisfaction (R2=0.1334). (5) Superivision factor : Shorter weekday working hours and larger number of monthly holidays make greater job satisfaction (R2=0.1709). (6) Achievement factor : Marriage, larger number of dietitians(R2=9.2293), age, larger number of monthly holiday, higher monthly wages and computer utiliazation (R2=0.1088) make greater job satisfaction. (7) Speciality factor : Marriage, longer current hospital tenure, higher position and working in seoul(R2=0.1142) make higher job satisfaction. (8) Job inclination factor : working in general hospitals rather than in oriental hispitals, working in seoul(R2=0.1776) and better bonuses(R2=0.1078)make greater job satisfaction. As a result, the following is suggested for the job satisfaction of hospital dietitions on the basis of this study : hospital dietitians can achieve miximum job satisfaction through smooth relationships with coworkers, and the responsible managers should improve welfare and working conditions for the job satisfaction of hospital dietitians.