• Journal of Astronomy and Space Sciences
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• 제22권2호
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• pp.175-186
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• 2005

본 논문에서는 정지궤도 통신위성인 무궁화위성 3호 버스 시스템을 모델로 하여 확장칼만필터를 이용한 자세결정 알고리즘을 개발하고 그 설계 결과를 시뮬레이션을 통해 제시하였다. 특히, 정확한 추정을 위한 칼만필터의 필터 이득을 결정하기 위해서는 초기에 입력된 추정변수들의 값에 변동이 없는 상황을 가정하게 되는데 본 연구에서는 2Hz 로 자세제어도 동시에 수행하면서 필터이득을 구하여 추정변수들의 값에 변동이 있는 상황에서도 필터가 정상적으로 동작됨을 보였다. 최종적으로 필터를 사용하지 않은 경우와 사용한 경우를 고려하여 4축 자이로의 각 바이어스가 있는 경우 및 개별적으로 자이로가 고장이 난 경우의 시뮬레이션 결과를 통해 설계된 필터가 자이로 이상상태를 대처할 수 있음을 검증하였다.

• 한국산업정보학회논문지
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• 제17권1호
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• pp.73-93
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• 2012

The primary objective of this research is to explain how to implement the Service Oriented Architecture (hereafter SOA) enabled Enterprise Resource Planning (hereafter ERP) system successfully for service industries. An implementation of the ERP system help many organizations to alleviate the difficult job of supporting inflexible or legacy systems that in most cases result in cost increases, data redundancy and inaccuracy, and various inefficiencies. However, the ERP system is losing its market share rapidly to the cloud computing system which utilizes the Software-as-a-service (hereafter SaaS) and SOA. The SOA is an approach to integrate various types of IT resources to leverage existing ERP system, while at the same time building an infrastructure that can readily respond to new business environment and offer new dynamic applications. The companies that implement this system have less of a need for the kinds of all-in-one ERP system that have dominated the back office for decades and can move freely to best-of-breed applications. This research will identify the benefits and costs of the SOA enabled ERP system through case studies and its impact on competitive priorities such as cost, quality, delivery, and flexibility.

• Safety and Health at Work
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• 제6권1호
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• pp.56-61
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• 2015

Frozen food processing workers work under a cold environment which can cause several adverse health effects.This study explored factors affecting workers' health in the frozen food industry in Thailand. Participants comprised 497 workers exposed to a cold working environment and 255 office workers who served as the controls. Data were collected by a survey on the work environment, and the interview of workers for abnormal symptoms. The exposed group had the following characteristics: 52.7% male, overall average age of 27 (SD 6.6) years old, attained elementary education (Grade 4 and Grade 6) (54.1%), married (48.9%), smokers (21.3%), alcohol consumption (31.0%), duration of work was between 1 and 5 years (65.2%), working 6 days a week (82.7%), 1-5 hours of overtime per week (33.8%), office workers (33.9%); work category: sizing (6.9%), peeling (28.3%) dissecting (22.2%), and in the warehouse (8.6%). The temperature in the work environment ranged from $17.2^{\circ}C$ to $19.2^{\circ}C$ in most sections, $-18.0^{\circ}C$ in the warehouse, and $25^{\circ}C$ in the office areas. Warehouse workers had more abnormal symptoms than controls including repeated pain in the musculoskeletal system (OR 11.9; 95% CI 6.12-23.45), disturbance throughout the body (OR 4.60; 95% CI 2.00-10.56), respiratory symptoms (OR 9.73; 95% CI 3.53-26.80), episodic finger symptoms (OR 13.51; 95% CI 5.17-35.33). The study results suggest that workers' health should be monitored especially with regard to back and muscle pain, respiratory symptoms, episodic finger symptoms, and cardiovascular symptoms. Health promotion campaigns such as antismoking and reduction of alcohol consumption should be established because smoking and alcohol consumption are contributing factors to the pathogenesis of Raynaud's phenomenon and peripheral vascular disorders such as hypertension and heart disease.

• 한국전문물리치료학회지
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• 제30권3호
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• pp.174-183
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• 2023

Background: Office workers experience neck or back pain due to poor posture, such as flexed head and forward head posture, during long-term sedentary work. Posture correction is used to reduce pain caused by poor posture and ensures proper alignment of the body. Several assistive devices have been developed to assist in maintaining an ideal posture; however, there are limitations in practical use due to vast size, unproven long-term effects or inconsistency of maintaining posture alignment. We developed a headphone and necklace posture correction system (HANPCS) for posture correction using an inertial measurement unit (IMU) sensor that provides visual or auditory feedback. Objects: To demonstrate the test-retest reliability and concurrent validity of neck and upper trunk flexion measurements using a HANPCS, compared with a three-dimensional motion analysis system (3DMAS). Methods: Twenty-nine participants were included in this study. The HANPCS was applied to each participant. The angle for each action was measured simultaneously using the HANPCS and 3DMAS. The data were analyzed using the intraclass correlation coefficient (ICC) = [3,3] with 95% confidence intervals (CIs). Results: The angular measurements of the HANPCS for neck and upper trunk flexions showed high intra- (ICC = 0.954-0.971) and inter-day (ICC = 0.865-0.937) values, standard error of measurement (SEM) values (1.05°-2.04°), and minimal detectable change (MDC) values (2.92°-5.65°). Also, the angular measurements between the HANPCS and 3DMAS had excellent ICC values (> 0.90) for all sessions, which indicates high concurrent validity. Conclusion: Our study demonstrates that the HANPCS is as accurate in measuring angle as the gold standard, 3DMAS. Therefore, the HANPCS is reliable and valid because of its angular measurement reliability and validity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1695-1700
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• 2011

In this paper, we introduce the network infrastructure in an advanced emu test line in Deabul. New technology has been applied to advanced EMU(DMU, integrated broadcasting system, black box and etc). In order to efficient and safely test of new developed train, failure, operation, status of test line and weather information should be monitored in real time. We has implemented a wireless and optical network infrastructure for reliability and scalability. The wireless communication capability between a car and ground is 20Mbps and back-hole network has 50Mbps of the communication performance. The network between test tracks and control office was established in the optical network. That can improve communication reliability.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 추계학술대회 논문집(제2권)
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• pp.163-166
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• 2006

본 논문에서는 지상송신국 기반의 로란-C 전파항법시스템이 위성항법시스템(GNSS)의 등장이후 급속한 이용자 감소로 운영의 효율성이 떨어짐에 따라 다양한 각도의 로란-C 성능평가를 실시하여 활용능률 향상방안을 제안하였으며, 국가항법시스템의체계인 관리를 위해 DGPS시스템과 로란-C를 연계한 GNSS 정보센터를 운영하여 GPS는 물론 Galileo, GLONASS 등 위성항법시템 전반의 상황을 모니터링하고 GNSS 불능 시 로란-C를 BACK-UP시스템으로 활용한다면 GNSS 장애로 인한 국가적대혼란의 예방함께 체계적인 전파항법시스템 관리가 가능할 것으로 결론하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.119.2-119
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• 2001

The inspection of a meter is an action that measures the amount of electricity, water and gas used to impose user on a charge. In past days, a meter who visit consumer to look over meter and write data to the ledger and then go back his office to calculates the inspection of a meter. On the other hand, the AMR(Automatic Meter Reading) is remote control system to measure the amount of utility used and monitor a condition of the meter. A study about AMRS is started at 1960 all over the world and a successful application example is presented continuously in American, Europe and Japan etc. In this paper we use a check meter that is used in past days and we add an AMR to it. AMR receives data that is the amounts of electricity from the check meter and stores those ...

• 대한수의학회지
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• 제22권2호
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• pp.233-237
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• 1982

Pathological studies on 6 milk goats administrated with urea were carried out to determine the effects of acute and chronic poisonings on the animal. Clinical signs appeared about 10 minutes after ingestion of the urea and they consisted chiefly in dullness, staggering, uncontrolled urination, dyspnea, frothy salivation, bloating, muscular tremor, humping of back and tetanic spasms. Macroscopic lesions were failure of blood clot, frothy and bloody contents in the highly congested respiratory tract, pulmonary edema, rumenitis and abomatitis accompanying with petechiation of the upper small intestine. Microscopically, the liver showed vacuolar degeneration, fatty change and areas of necrosis and partial proliferation of the interlobular connective tissues in chronic crises. The renal epithelium displaced vacuolar degeneration, necrosis and hyaline casts in their lumens. In the lungs, there were hyperemia, edema, hemorrhages, and acute catarrhal bronchitis. Neuronal degeneration and necrosis in the central nervous system, catarrhal rumenitis, abomatitis, doudenitis and myocardial hemorrhage were also demonstrated.

• 한국전자파학회논문지
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• 제22권4호
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• pp.453-461
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• 2011

방송 대역의 한정된 주파수 자원을 보다 효율적으로 사용하고, 지상파 방송의 난시청 지역 해소와 방송 품질 향상을 위해 중계기의 중요성은 계속적으로 증가하고 있다. 그러나 OFDM 시스템의 T-DMB 동일 채널 중계기는 전송된 신호의 일부가 궤환되어 다시 수신 안테나에 입력되는 궤환 간섭 신호가 발생하고, 위상 잡음(phase noise)으로 인한 ICI(Inter Carrier Interference)가 증가하여 등화기에 심각한 영향을 미친다. 그러므로 본 논문에서는 상관도를 적용한 LMS(Least Mean Square)를 이용하여 궤환 간섭 신호를 제거한다. 또한, 전력 증폭기(high power amplifier)의 백-오프 특성과 위상 잡음에 의해 발생하는 ICI를 제거할 수 있는 효과적인 등화 알고리듬을 제시한다. 시뮬레이션 결과를 통하여 back-off=9 dB 상태에서 위상 잡음 -20 dBc의 경우 위상 잡음을 보상하여 SNR=14 dB 이하에서 BER=$10^{-4}$의 성능을 만족할 수 있다.

• Journal of Power Electronics
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• 제14권5호
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• pp.957-966
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• 2014

Some of DC actuators used in home automation, office automation, medical equipment and automotive systems require a position sensor. In low power applications, the introduction of such a transducer remarkably increases the whole system cost, which justifies the development of sensorless position estimation techniques. The well-known AC motor drive sensorless techniques exploiting the fundamental component of the back electromotive force cannot be used on DC motor drives. In addition, the sophisticated approaches based on current or voltage signal injection cannot be used. Therefore, an effective and inexpensive sensorless position estimation technique suitable for DC motors is presented in this paper. This technique exploits the periodic pulses of the armature current caused by commutation. It is based on a simple pulse counting algorithm, suitable for coping with the rather large variability of the pulse frequency and it leads to the realization of a sensorless position control system for low cost, medium performance systems, like those in the field of automotive applications.