• 대한기계학회논문집A
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• 제24권6호
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• pp.1371-1378
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• 2000

To reduce backpressure for improving engine power in exhaust system, a large difference of pressure is required, but this is in conflict with the requirement for reducing exhaust noise that needs a small pressure difference. In this paper, the controllable muffler designed by simplifying the structure of the exhaust system has a low backpressure and a proper sound specification to the rotation of engine. The exhaust system in conventional studies has been designed to have maximum noise reduction over the whole driving domain, but due to its complex structure this led to increased backpressure. If the muffler is designed according to the driving frequency, which is a dominant noise component in stationary driving speed, the backpressure is reduced due to the simplified structure of the muffler. Furthermore, a multi-mode muffler able to change structure with varied driving speed was designed.

• 한국산업정보학회논문지
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• 제23권3호
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• pp.131-142
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• 2018

Since income growth rate and poverty level are related, there is a possibility that the poverty rate may converge in the long run steady state as well. If the poverty rate converges, then for this study the state that begins with the high poverty rate would have a higher poverty reduction rate. To examine the convergence of poverty rate among the US states, this study uses two times series methodologies. First, in order to prevent the power loss from ignoring the structural break when testing for a unit root in a single time series, this study employs the newly developed panel LM unit root tests with level and trend shifts. The results of unit root tests of the log of poverty rate without allowing for structural breaks show that twenty six states reject the null hypothesis of unit root test for the ADF test, twenty five states for the LM test, and thirty five states for the RALS-LM test. The result of unit root tests that allow one structural break shows that the null hypothesis of a unit root test is rejected for twenty two states with the LM test, and thirty three states with the RALS-LM test. This supports poverty rates are converging among US states.

• ETRI Journal
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• 제31권3호
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• pp.254-262
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• 2009

This paper presents a novel simple filter design method based on a parallel short-ended coupled-line structure with capacitive loading for size reduction and ultra-broad rejection of spurious passbands. In addition, the introduction of a cross-coupling capacitor into the miniaturized coupled-line can create a transmission zero at the second harmonic frequency for better frequency selectivity and attenuation level. The aperture compensation technique is also applied to achieve a strong coupling in the coupled-line section. The influence of using the connecting transmission line to cascade two identical one-stage filters is studied for the first time. Specifically, such a two-stage bandpass filter operating at 2.3 GHz with a fractional bandwidth of 10% was designed and realized with low-temperature co-fired ceramic technology for application in base stations that need high power handling capability. It achieved attenuation in excess of -40 dB up to $4f_0$ and low insertion loss of -1.2 dB with the size of 10 mm ${\times}$ 7 mm ${\times}$ 2.2 mm. The measured and simulated results showed good agreement.

• 기본간호학회지
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• 제17권4호
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• pp.557-565
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• 2010

Purpose: This study was conducted to investigate the factors influencing the quality of life among the patients with Crohn's disease. Method: Data were collected from 97 Crohn's disease patients between September 17 and October 20 in 2009. The collected data were analyzed by SPSS program. Results: There were significant differences in the participants' quality of life depending on their age, economic status, pain, diarrhea, weight loss, Crohn's disease activity index (CDAI), and use of medications such as antidiarrhotica, steroid, and analgesics. The results also showed the correlations between the participants' qualities of life and thier pain, CDAI, anxiety, depression, perceived health condition, and of body image. Finally, the factors affecting the quality of life in patients with Crohn's disease included anxiety, perceived health state, pain, and CDAI. The explanatory power of these factors was 79.5%. Conclusion: The results imply that controlling the patients' pain and providing emotional support for anxiety reduction are crucial. In a similar vein, tailored nursing interventions considering individual patients' conditions are believed to help the patients positively perceive their disease. A future research, can conduct further investigations of these factors from more diverse perspectives, which is expected to promote more effective nursing strategies for Crohn's disease patients.

• 전기학회논문지
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• 제63권12호
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• pp.1627-1636
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• 2014

In real-time electricity price environment, the energy management system can provide the significant advantage to the residential, commercial and industrial customers since it can reduce the electricity charge by controlling the load operation effectively in response to time-varying price. However, the earlier studies for load management mainly focus on the residential and commercial customers except for the industrial customers because most of load operations in industrial sector are intimately related with production schedule. So, it is possible that the inappropriate control of loads in industrial sector causes huge economic loss. In this paper, therefore, we propose load control algorithm for factory energy management system(F-EMS) to achieve not only minimizing the electricity charges but also maintaining production efficiency by considering characteristics of load operation and production schedule. Considering characteristics of load operation and production schedule, the proposed load control algorithm can reflect the various characteristics of specific industrial customer and control their loads within the range that the production efficiency is maintained. Simulation results show that the proposed load control algorithm for F-EMS leads to significant reduction in the electricity charges and peak power in industrial sector.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.95-101
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• 2012

An electric water pump for engine cooling system has an advantage which particularly in the cold start, the use of the electric water pump saves fuel and leads to a corresponding reduction in emissions. The canned type electric water pump without mechanical sealing elements was selected to meet the requirements for operational reliability and life. However, the electric water pump for internal combustion engine generates much more heat loss than for hybrid electric vehicle since it is operated by the electric power of high current and low voltage. In this study, the fluid flow and thermal characteristics of the canned type electric water pump as an inverter integrated water pump has been investigated under the effects of heat generation. The analysis conditions such as outdoor air temperature of $125^{\circ}C$, water pump speed of 6000 rpm, coolant temperature of $106^{\circ}C$ and coolant flow rate of 120 L/min was used as a standard condition. Therefore, flow fields and temperature distribution inside the water pump were obtained. Also, we checked the feasibility of the canned type for the electric water pump in comparison with the mechanical seal type.

• Agricultural and Biosystems Engineering
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• 제5권2호
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• pp.40-44
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• 2004

This study was conducted to solve the problem of spinach harvesting done by manpower at the outdoor field during the cold winter season. Prototype spinach harvester was designed to dig, pick-up, and collect in a continuous operation for harvesting outdoor field-planted crawling type spinach. In the field test, two types of blades (Type A : angle of $150^{\circ}$, Type B : straight) were used for measuring the cutting loads of spinach and chain conveyor with lugs was used for picking up the root cut spinach. Prototype's vibrating blade reduced the digging power of the fixed blade by $46\%$. The loss was also very little ($0.7\%$) with a digging depth of 4 cm, an oscillation frequency of 748 rpm, and an oscillation distance of 33 mm. The working performance of the prototype spinach harvester was 38 hour/ha resulting to $96\%$ labor cost reduction compared to the conventional harvesting.

• 한국자동차공학회논문집
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• 제16권6호
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• pp.65-73
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• 2008

The purpose of this study is development of universal engine model for integrated Hybrid Electric Vehicle (HEV) simulator and a optimization of engine model. The engine model of this study is based on the MATLAB Simulink for universal and include engine fuel economy technologies for HEV. Various engine fuel economy technologies for HEV is estimated by commercial engine 1-D simulation program - WAVE. And, the 1-D simulation model of base version is compared with engine experiment result. The analyzed engine technologies with 1-D simulation are Dual-CVVT, Atkinson-Cycle and Cylinder-Deactivation System. There are improvement of fuel economy and power performance with Dual-CVVT model at part load and full load, pumping loss reduction with Cylinder-Deactivation System at idle and regeneration. Each estimated technologies are analyzed by 1-D simulation on all operation region for base data to converse simulink. The simulink based engine model maintains a signal with ECU for determination of engine operation point.

• 한국광학회지
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• 제12권4호
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• pp.289-293
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• 2001

금속 모세관을 이용하여 일반적인 단일모드 광섬유를 결합함으로써 매크로 벤딩(macro bending)을 측정할 수 있는 광섬유 센서를 제작하였다. 매크로 벤딩에 의한 곡률 반지름이 감소함에 따라 각도 정렬 오차가 증가하여 투과되는 빛의 에너지가 감소하게 되므로 매크로 벤딩을 측정할 수 있었다. 측정 범위는 곡률 반지름 20mm에서 85mm의 영역이었다. 사용한 광섬유 격자의 중심 파장은 각각 1543.3 nm, 1549.5nm이고 최대 벤딩 손실을 -11.19dB였다. 이 센서와 광섬유 브래그 격자를 이용하여 다중점 측정이 가능함을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.331-334
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• 1997

The electrical and physical charateristics of aluminum oxide and Pt thin films on it, deposited by reactive sputtering and DC magnetron sputtering, respectively, were analysed with increasing annealing temperature(400~80$0^{\circ}C$) by four point probe, SEM and XRD. Under $600^{\circ}C$ of annealing temperature, aluminum oxide had the properties of improving Pt adhesion to SiO$_2$and insulation without chemical reaction to Pt thin films and the resistivity of Pt thin finns was improved. But these properties of aluminum oxide and Pt thin finns on it were degraded over $700^{\circ}C$ of annealing temperature because aluminum oxide was changed into metal aluminum and then reacted to Pt thin films deposited on it. The thermal characteristics of Pt micro heater were analysed with Pt-RTD integrated on the same substrate. In the analysis of properties of Pt micro heater. active area was smaller size, Pt micro heater had better thermal characteristics. Temperature of Pt micro heater fabricated on membrane was up to 34$0^{\circ}C$ with 1.2watts of the heating power due to reduction of the external thermal loss.