• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.3
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• pp.74-82
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• 2011

This paper describes a control system for positioning the real-time locations of the autonomous warfare vehicles and infantry, and for avoiding collisions between them. The control system utilizes the low-cost RSSI (Received Signal Strength Indication) for positioning the locations of the wireless devices. The mathematical mean filtering processes are applied to the calculation of the RSS matrix to improve the performance for positioning the wireless devices in the multi-path propagation environment. A fuzzy rule is proposed to recover and replace the broken packets occurring in the wireless communication. The gradient and geometric triangulation algorithms are proposed to trace the real-time locations of wireless devices, based on the distances between them. The estimated location results of the geometric triangulation algorithm are compared with the results of the GPS and the gradient algorithm.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.506-511
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• 2017

LED lighting, which many companies are pursuing commercialization, is a representative green energy technology. However, the LED lighting for broadcasting image should have high output and easy portability compared with general LED lighting devices for street lamps, advertisement or transportation devices. Therefore, while shooting a broadcast image if you use LEDs as a substitute light source for halogen lamps and fluorescent lamps that are large in size and uncomfortable to handle it is expected that the lightening of the equipment will activate the broadcasting image lighting equipment industry. After considering the mass production of the LED module board and the SMT production size of the chip mounter, the board size was determined considering the overall size of the product by model. In this paper, four 20W LED boards are arranged vertically in order to produce an 80W board. In other words, by sharing LED module board size by model, high power LED lighting equipments of 120W and 200W can be selected as an increase in the number of boards.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.470-470
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• 2023

하천 및 저수지의 수량자료 수집을 위해 부자식 또는 레이더식 수위계 등의 계측기를 이용하여 수위의 변화를 측정한다. 그러나, 수량 모니터링을 위해 설치되는 계측기와 유지관리를 위한 인력소모 비용의 이유로 일부 지역에서만 제한적으로 수행되고 있어 정확한 수문 해석에 한계가 있다. 이에 본 연구에서는 저가의 센싱장비와 라즈베리파이를 활용한 ICT 기술을 수량 모니터링분야에 적용하여 수위 모니터링 기술을 개발하고자 한다. 라즈베리파이(Raspberry Pi 3 B Model)는 오픈소스 기반의 초소형 컴퓨터로 여러 센서를 연결하여 다양한 수문 인자(토양수분, 온도, 수위 등)들을 측정할 수 있으며, 통신 모듈이 기본 내장되어 있어 통신망 구축을 통해 측정데이터를 데이터베이스에 저장할 수 있다. 수위센서(eTape)와 초음파센서를 연결하여 실제 하천 유량 모니터링에 활용되고 있는 부자식 수위계 장비와 비교 분석을 통해 활용 가능성을 검증하고자 하였다. 검증방법은 인공강우실험을 위해 설치된 플륨관에 수위센서(eTape)와 초음파센서를 부착하여 기존 운영중인 부자식 수위계와 비교하였다. 부자식 수위계의 측정결과와 두 센서의 상관관계를 분석한 결과 결정계수(R²)가 0.94 이상으로 나타났다. 분석결과와 같이 기존 고가의 수위 관측장비들을 대체하여 저가의 센서 기반 모니터링 장비들의 실용화가 가능할 것이라 판단된다. 향후 연구에서는 다양한 센서(수위, 초음파, 카메라 등)를 이용하여 농업용수 물수지 분석에 활용할 계획이다. 농업용수는 수자원 총량 중 차지하는 비율이 높음에도 불구하고 정량적 데이터가 부족한 실정이며, 지역별 공급 특성이 다양하여 이를 계량화하기 위해서는 다수의 계측기가 필요하다. 따라서, 본 연구에서 개발중인 센서를 활용하여 물순환 과정의 정량적인 계측을 통해 농업용수의 효율적인 관리 및 농업용수의 하천기여도 평가 자료로 활용될 수 있을 것으로 판단된다.

• The Korean Journal of Applied Statistics
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• v.29 no.3
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• pp.549-557
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• 2016

Consecutive missing values are likely to occur in long climate data due to system error or defective equipment. Furthermore, it is difficult to impute missing values. However, these complicated problems can be overcame by imputing missing values with reference time series. Reference time series must be composed of similar time series to time series that include missing values. We performed a simulation to compare three missing imputation methods (the adjusted normal ratio method, the regression method and the IDW method) to complete the missing values of time series. A comparison of the three missing imputation methods for the daily mean temperatures at 14 climatological stations indicated that the IDW method was better thanx others at south seaside stations. We also found the regression method was better than others at most stations (except south seaside stations).

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.2
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• pp.49-57
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• 1997

It is necessary to conduct researches about seismic design and analysis to protect various structures from earthquakes which are one of the most destructive natural disaster to human civilization. To assess the seismic capacity of structure, not only analytical but also experimental researches are important. Currently, pseudodynamic test known as computer-actuator on-line test is one of the available test methods to assess seismic capacity of structure without using shaking table. In this paper seismic capacity of simple one-degree of freedom structure was estimated by pseudodynamic test. Good agreement between the experimental and analytical results was obtained. Better results would be obtained when more sophisticated measuring and controlling instruments are available.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1139-1144
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• 2019

A calibration system for diagnosing and confirming the performance of precision measuring instruments minimizes the risk of misjudgment of calibration resulted by complying with international standard requirements in order to ensure the reliability of calibration results. This paper uses a proposed calibration system suitability assessment and a guard-band technique through an analysis of uncertainty factors when it is impossible to acquire and operate high-performance equipment at a calibration laboratory, and proposes an optimized test limit output model substituting performance standards. The proposed method provides an optimized test standard to meet the quantitative evaluation criteria of the calibration system and the probability of false acceptance risk required by international standards.

• The Journal of Information Technology
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• v.6 no.3
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• pp.1-10
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• 2003

This paper is concerned with a power line channel modeling for the more fast and efficiently power line communication experiment. A capacitor load channel simulator is a essential equipment in the power line modem development for in-house network. We accomplished a channel modelling by the frequency response method about the total 298 capacitor load channels. This channel data is acquired by the capacitor load simulator modeling a real power line channel environment. When the experiment results acquired from the capacitor load simulator were compared with the result from a channel filter, we confirmed to substitute capacitor load experiments on the actual power line communication without big error.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.13-19
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• 2015

The wood pellet is standardized of woody type fuel which of small cylindrical shape that is produced compress wood remnants in process of woody processing. The pellet is critical energy which expects to increase of the amount used in future. It consumes fuel which of home, common facilities stove and boiler, district heating, and CHP, etc. This study was to develop a movable pellet manufacturing equipment that can be mounted on a truck. The pellet production volume is approximately 309kg per hour, daily output is about 2ton. One days work based on the expected revenue of approximately \268,000 feasibility is considered sufficient.

• Journal of the Korea Society for Simulation
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• v.25 no.2
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• pp.75-81
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• 2016

By using simulation, fixed location production method and flow production method have been compared to improve the productivity of deckhouse preceding outfitting process. In this paper, we analyze that the suggested flow production system instead of fixed location production can improve productivity. In current preceding outfit production system which adopts fixed location production, where a block occupies an area and does not move until the work finishes. On the other hand, in improved flow production system, the block moves instead of workers and equipment. Though the output of two systems are almost the same when we did not consider the moving time and waiting time of blocks, the flow production will be better when the variability of task time will be reduced.

• Journal of Technology Innovation
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• v.1 no.1
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• pp.84-99
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• 1993

오래도록 생산성향상곡선 (또는 학습곡선), 생산함수, 그리고 대체곡선 등은, 서로 관련이 없는 별개의, 그리고 순전히 경험적인 (empirical) 현상들인 것들로서 이해되어 왔었다. 그러나 1980년대 중반에 발표된 Muth 교수의 탐색이론 (Search Theory)의 생산성향상곡선에서 관찰된 제반현상들을 모두 설명함으로써 이들 현상은 하나의 통합이론체계에 의하여 일관되게 설명되게 되었다. 이 이론의 초기형태는 그 보편성을 구속하는 네 가지 가설 위에 설립되었었으나 점차적으로 이들 가설들이 완화되면서 (relaxed) 이 이론은 또한 해독 력에서 뿐만 아니라 일반성에 있어서도 계속 강화되어 왔다. 본 논문의 목적은, 이들 네 가지 가설들 중 유일하게 아직 완화되지 못하고 있는, 실제 현상과 다분히 유리된, 두 번째 가설, 즉$\ulcorner$생산성향상을 위한 탐색과정에서 새로이 발견된 개량 신기술 (또는 생산방식) 은 즉각적으로 채택될 것$\lrcorner$이라는 가설을 완화함으로써, 보다 현실에 대한 해석력과 일반성 면에서 개선된 모델을 제시하는 데 있다. 이를 위하여 제시된 모델은 Muth 교수의 탐색이론모델에 두가지 변수를 더함으로써 확장하여 만든 모델이다. 이 두 변수는 신기술의 채택 (또는 획득)을 위하여 지불하여야 하는 투자비변수와 탐색과정을 통하여 발견은 되었으나 아직 채택은 되지 않은, 유보상태 신기술의 운영비용 변수(또는 수익성변수)등이다. 이 모델의 내용은, 생산성향상은 신기술이 구현된 (embodied) 장비 (equipment)를 사용함으로써 실현되며, 따라서 창의적 활동의 이득은 이들 장비에 대한 투자행위로서 실현된다는 것이다. 이 모델은 보다 나은 신기술이 또 발견될 것이라는 기대 하에, 현재 발견된 최신기술을 채택하지 않는 투자지연현상을 예측.설명해 주며 따라서 이로 인한 기술적 비효율성의 존재이유를 제시한다. 또한 이 모델은 생산성 향상곡선의 초기굴곡현상, 정체현상, 그리고 도약현상 등을 모두 설명해 준다.