• Nutritional Sciences
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• 제8권2호
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• pp.89-96
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• 2005

To determine the deleterious effects of chronic alcohol consumption on bone especially in adolescents or young adults, 8 week-old Sprague Dawley male rats were fed with Lieber-Decarli ethanol liquid diet, containing $36\%$ of energy as ethanol, ad libitum (ethanol group) or isocaloric normal liquid diet (control group) for 7 weeks. Body weight was significantly lower in ethanol group than that in control group after 1 week of feeding to the end. liver weight and the ratio of liver or kidney weight to body weight in ethanol group were significantly increased when compared to those in control group. Ethanol group showed significantly lower serum protein and albumin levels (p<0.05), higher total cholesterol and HDL-cholesterol levels (p<0.05), and AST, ALT and BUN activities than control group, but serum triglyceride, Ca and phosphate levels were not different. Ethanol group had significantly lower tibial trabecular bone area and serum osteocalcin level than control group (p<0.05), but urinary Ca and NTx (cross-linked N-telopeptide of type I collagen) concentrations and serum testosterone and parathyroid hormone levels were not different. In conclusion, chronic alcohol consumption in growing young male rats may result in osteopenia through the reduction of bone formation as well as liver malfunction.

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.30-38
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• 2018

Electronic control units (ECUs) are currently popular, and have evolved further towards the high-end application of autonomous vehicles in the automotive industry. Such digital technologies have also become widespread, in agriculture and construction equipment. Likewise, transmission control of high-speed tracked vehicles is based on the transmission control unit (TCU), performing complex gear change control functions, and diagnostic algorithms (a TCU's self-diagnostic and reporting capability of malfunction data through CAN communication). Since all functions of TCU are implemented by embedded-software, it is hardly possible to analyze specifications by reverse engineering. In this paper a real-time transmission simulator adaptable to TCU is presented, for analysis of diagnosis algorithm and standards. Signal simulation circuits are deliberately designed considering electrical characteristics of TCU inputs and various analysis tools, such as analog input auto scan function, and global output enable switch, are implemented in software. Test results from hardware-in-the-loop simulator verify tolerance time for each error, as well as cause of fault, error reset conditions.

• 한국소음진동공학회논문집
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• 제26권2호
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• pp.165-171
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• 2016

A prosthetic knee for above-knee (AK) amputee is categorized into passive and active type. The passive prosthetic knee is generally made by elastic material. Although AK amputee can easily walk by using passive prosthetic leg, knee joint motions are not similar to ordinary persons. The active prosthetic leg can control the knee angle owing to the actuator and microprocessor. However, the active type is not cost-effective and the stability may be lost due to the malfunction of sensors. In order to resolve these disadvantages of passive and active type, a semi-active prosthetic knee which can control the knee angle is proposed in this work. The proposed semi-active one requires a less input energy but provides active type performance. In order to achieve this goal, in this work, a semi-active prosthetic knee using magneto-rheological (MR) damper for AK amputees is designed. The MR damper can support the weight of body by using less energy than actuator of active prosthetic. It can control knee angle by inducing the magnetic field at the time of stance phase. This salient characteristic is evaluated and presented in this work.

• 한국소음진동공학회논문집
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• 제26권5호
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• pp.552-558
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• 2016

A control rod drive mechanism(CRDM) is a reactor regulating system, which inserts, withdraws or maintains a control rod within a reactor core to control the reactivity of the core. The CRDM for Jordan Research and Training Reactor with 5MW power has been designed and fabricated based on the HANARO’s experience through KAERI and DAEWOO consortium. This paper describes the seismic test results to demonstrate the operability, the drop performance and the structural integrity of CRDM during or after seismic excitations. The seismic tests are carried out under 5 OBE and 1 SSE loads at three Test Rigs simulating the reactor structure and the pool top. From the tests, the CRDM is smoothly driven without a malfunction of stepping motor under OBE load. The pure drop time under OBE and SSE loads is measured as 1.169s and 1.855s to meet the design requirement. Also, it is found that the CRDM maintains the structural integrity without a change of the function and natural frequency before and after seismic loads.

• 한국자동차공학회논문집
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• 제22권4호
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• pp.89-97
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• 2014

As the digital control technologies in automotive industry have advanced, electronic control units(ECUs) play a key-role to improve system performance. Transmission control unit(TCU) is a shifting controller for automatic transmission of which major functions are to determine the shift and manage the shifting process considering the various sensor signal on transmission and driver's commands. As with any ECU in vehicle, TCU performs complex algorithms such as shift control, diagnostic and failsafe functions. However, firmware design analysis is hardly possible by the reverse engineering due to code protection. Transmission simulator is a hardware-in-the-loop simulator which enables TCU to work in normal mode by simulating the electrical signal of TCU interface. In this research, diagnosis and failsafe algorithm implemented on commercialized TCU is analyzed by using the transmission simulator that is developed for wheel loader construction vehicle. This paper gives various experimental results on the proportional solenoid current trajectories for different operating modes, error detection criterion and limphome mode gears for all the possible cases of clutch malfunction. The derived results for conventional TCU can be applied to the development of inherent TCU algorithms and the transmission simulator can also be utilized for the test of TCU to be developed.

• Journal of Welding and Joining
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• 제32권1호
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• pp.102-107
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• 2014

SCR(Thyristor) type $CO_2$ welders have widely used for the welding process of heavy industries such as shipbuilding and plant. Since the industrial fields of shipbuilding and plant are usually exposed to severe welding condition with lots of dust, extreme temperature, high humidity and vibration, it is not recommended to use inverter type welder despite its state-of-the-art technology. Many sophisticated functions in the inverter welder may not work due to malfunction of its sensitive components. Hence this study focused on digitalization of SCR $CO_2$ welder by making use of microprocessor for SCR phase control. By this application, fine control of output of the $CO_2$ welding systems is achieved. Also pulse output mode of operation is realized and its verification is carried out with aluminum sample welding. The experimental results showed sound weld bead. The front operation panel provide user with numerical parameter settings and monitors. It will help precise weld process monitoring and control with digital value.

• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.539-546
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• 2006

The Air Quality Sensor(AQS), located near the fresh air inlet, serves to reduce the amount of pollution entering the vehicle cabin through the HVAC(heating, ventilating, and air conditioning) system by sending a signal to close the fresh air inlet door/ventilation flap when the vehicle enters a high pollution area. The sensor module which includes two independent sensing elements for responding to diesel and gasoline exhaust gases, and temperature sensor and humidity sensor was designed for intelligent AQS in automobile. With this sensor module, AVR microcontroller was designed with back propagation neural network to a powerful gas/vapor pattern recognition when the motor vehicles pass a pollution area. Momentum back propagation algorithm was used in this study instead of normal backpropagation to reduce the teaming time of neural network. The signal from neural network was modified to control the inlet of automobile and display the result or alarm the situation in this study. One chip microcontroller, ATmega 128L(ATmega Ltd., USA) was used for the control and display. And our developed system can intelligently reduce the malfunction of AQS from the dampness of air or dense fog with the backpropagation neural network and the input sensor module with four sensing elements such as reducing gas sensing element, oxidizing gas sensing element, temperature sensing element and humidity sensing element.

• 에너지공학
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• 제25권1호
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• pp.163-170
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• 2016

전자 제어 가속 시스템에서, APS 센서는 운전자의 의지를 반영하는 가장 중요하고 유일한 부품이다. 특히, 참조센서가 없는 형식의 APS는 이 시스템에 있어서 상당히 중요한 영향을 미칠 수 있는 부품이 아닐 수 없다. 이러한 형식의 부품은 참조 값을 제공할 수 없기 때문에 고장 상황에서 운전불능 상태나 고장 복귀모드 진입이 더욱 용이할 수 있다. 만약 이러한 상황이 발생하게 되면, 이는 특히 전장에서 운전자와 군인 그리고 전쟁 물자 관리에 매우 위험한 조건이 될 수 있다. 전자제어 시스템이 전술 차량에 있어서는 반드시 필요한 시스템이 아니라고 할 수 있다. 오히려 전술 차량은 군인의 생명과 전쟁 물자를 보호, 구명, 탈출하기 위해 반드시 전자제어 시스템으로부터 독립된 수동제어 시스템이 준비되어 있어야 한다. 그리하여, 파손되어 수분이 침투된 경우의 APS 출력에 대한 연구를 하게 되었다. 만약 운전자의 의지와 무관하게 출력값이 변화된다면, 참조센서가 있는 형식의 APS라 할지라도, 이는 조정 불가능한 엔진 회전속도 변화 또는 고장복귀 모드에서의 성능 저하에 영향을 미치며, 이는 어떤 종류의 APS가 적용된 경우에도 전술 차량에 수동제어 시스템이 필요하다는 것을 알 수 있었다.

• 전자공학회논문지
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• 제51권11호
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• pp.205-210
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• 2014

본 연구는 도자기의 표면에 무늬, 모양, 그림, 글씨 등의 문양을 움직이는 효과를 갖는 광응용 시스템에 관한 것으로, 도자기 표면 문양에 부착된 광섬유에 의한 LED광신호를 이용하여 문양의 움직임 효과를 실시간으로 표출하고, 도자기가 있는 장소의 조도와 회전판의 움직임을 수집하여 큐레이터가 응급조치를 취하고 문양의 표출효과를 관리하기 위한 광응용 시스템에 관한 것이다. 이와 같은 본 연구에 의하면, 도자기가 놓여져 있는 장소의 조도를 측정하여 문양의 표출효과를 큐레이터 및 응용프로그램이 실시간 관리할 수 있음과 동시에, 이상 발생 시에 자동으로 신호를 발생하여 조치할 수 있게한다. 또한, 본 연구은 일정기간 동안 광신호 전송데이터를 메모리에 저장하였다가, 데이터베이스화하여, 표출효과를 분석 후, 최적의 표출효과를 갖도록 적절한 조치를 취할 수 있도록 한다. 도자기가 있는 장소의 조도 상태를 감지 및 전달하고, 적정한 판단을 내릴 수 있는 일정한 조도수치를 데이터베이스화하고, 적절한 조건에 의거 문양 표출관련 광섬유 색체, 표출간격과 밝기에 대한 신호 데이터가 강제 혹은 의도에 의한 전달이 이루어지게 한다. 따라서 본 연구의 목적은 관제센터의 응용프로그램과 LED제어모듈에 의해 발생되는 광송출신호를 생성하여 색채, 조도, 표출간격을 측정하고 전송할 수 있는 문양을 움직이는 효과를 갖는 광응용시스템을 연구하였다.

• 항공우주기술
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• 제4권1호
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• pp.57-65
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• 2005

정지궤도위성과 같은 차세대 대형위성의 우주궤도환경 모사를 위해 한국항공우주연구원은 유효직경 Φ8m, 유효길이 L10m의 대형 열진공챔버를 구축해오고 있다. 우주환경은 고진공 환경이며 태양 복사열에 의한 고온 환경 및 극저온이 반복되는 가혹한 환경으로 특징지어진다. 가혹한 우주환경에 의해서 위성체의 주요부품에 기능장애가 초래되기도 하고 이는 결국 임무의 실패로 이어지기도 한다. 위와 같은 이유들로 인하여 위성체는 지상에서 우주환경시험을 거쳐 기능 및 작동상태를 점검해야 하며, 이를 위해서는 우주환경을 모사할 수 있는 우주환경 모사장비가 필요하다. 본 논문에서는 대형 열진공 챔버를 효율적이고, 안정적으로 구동을 위한 모든 제어로직이 포함되어 있다.