• 수산해양기술연구
• /
• 제50권1호
• /
• pp.83-88
• /
• 2014

A new shell divider was manufactured according to the principle of the lever in order to improve working efficiency in collecting the gonad of Sea Urchin, Anthocidaris crassispina, around the coast of jeju. It was composed of three parts of a pair of handles for grasping power, a fulcrum and a pair of knives for action with 21cm in length and 13cm in width. The operating efficiency of the shell divider was tested out in three place of Jeju coast. Statistical significances of differences of working time between test groups were calculated according to the t-test with the level of significance. In dividing the shell of sea urchin, the average of about 3 seconds of working time by the shell divider was less than that by a knife. At the result of t-test, the statistical significance in the working time existed between the divider group and the knife group. On the other hand, the working time among the divider operators showed no significant differences. It is concluded that the shell divider is more efficient than a knife in traditional operating.

• 한국통신학회논문지
• /
• 제31권10C호
• /
• pp.1011-1022
• /
• 2006

최근 유무선 네트워크는 IP 코어망을 중심으로 가입자망의 형태를 가지는 BcN(Broadband convergence Network)로 진화되고 있으며, 이와 함께 인간 외부환경의 감지를 수행할 유비쿼터스 센서네트워크(USN : Ubiquitous Sensor Network)가 새로이 연구되어 오고 있다. 감지하는 대부분의 데이터의 경우에 악의를 가진 노드에게 노출되거나 위변조 되어서는 안될 정보들이기 때문에 센서네트워트에서 에너지 효율을 고려한 정보보호 기법을 요구한다. 본 논문에서는 임의의 센서노드부터 싱크까지의 에너지 효율적이고 안전한 데이터 전달을 위한 정보보호기법으로, 단순한 해쉬함수의 계산을 중심으로 에너지 소모를 줄이는 키관리기법을 제안하였다. 제안하는 키관리기법의 보안성 분석을 위하여 만족해야 하는 보안성에 대해 정의 증명하였으며, 에너지효율성을 측정하였다. 각 기법은 기존의 관련연구와 비교 분석하여 본 논문에서 제안한 기법이 우수함을 증명하였다.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
• /
• pp.93-98
• /
• 2011

A photovoltaic/thermal(PVT)collector produces both thermal energy and electricity simultaneously. The heat from PV modules should be removed for better electrical performance, and can be converted into useful thermal energy. A PVT module is a combination of PV module with a solar thermal collector which forms one device that converts solar radiation into electricity and heat. In general, there are two different types of PVT module: glazed PVT module and unglazed PVT module. On the other hand, two types of the PVT module can be distinguished according to absorber on PV module rear side: the sheet-and-tube absorber PVT module and the fully wetted absorber PVT module. The absorber collector plays an important function in PVT system. It cools down the PV module, while collecting the thermal energy produced in the form of hot water. The aim of this study is to compare the electrical and thermal performance of two different PVT collectors, one with the rectangular tube and the other with fully wetted absorber PVT collectors. For this paper, the PVT collectors with two different types of thermal absorber were made, and both the thermal and electrical performance of them were measured in outdoor, and the results were compared. The experimental results were analyzed that the thermal efficiency of the fully wetted absorber PVT collector is about 8.7% higher than the sheet-and-tube absorber PVT collector, and for the electrical efficiency, the fully wetted absorber PVT collector had about 7% higher than the rectangular tube absorber.

• 한국정밀공학회지
• /
• 제29권1호
• /
• pp.19-24
• /
• 2012

We demonstrate the desert beetle back mimicking hybrid superhydrophilic/superhydrophobic patterned surface by using the combination method of colloidal lithography and gravure offset printing for nano and micro patterning, respectively. The two methods are cost-effective and industrially available techniques compared to the other nano/micro patterning methods. To verify the water collecting function of the hybrid surface, the water condensation behavior is investigated on the chilled surface in ambient temperature and high humidity. Due to the synergetic effect of drop and film wise condensation, the hybrid superhydrophobic/superhydrophilic surface shows the higher efficiency than one of single wettability surfaces. The work is underway to get the good patterns of hybrid surfaces for water collecting from the dew or fog.

• 한국통신학회논문지
• /
• 제36권11B호
• /
• pp.1394-1402
• /
• 2011

본 논문은 포물 반사경 방식 및 프레넬 렌즈 방식을 이용한 태양광 집광장치 및 이의 응용에 관한 것이다. 본 시스템은 대구경 반사경과 더불어 2차 광학계를 도입하여 광섬유로 입사되는 빛의 입사각을 광섬유의 개구수보다 작게 함으로써 집광효율을 극대화하였다. 또한 광섬유 단면에 입사하는 빛의 에너지 밀도를 낮게 하기 위해 광섬유 다발 직경 크기와 동일한 평행광이 광섬유로 입사되게 함으로써 반사경을 사용한 집광 시 문제가 되는 열발생 문제를 별도의 냉각장치 없이 근원적으로 차단하였다. 최근 각광받고 있는 식물공장에 주로 쓰이는 LED와 같은 인공광원 대신 본 연구에서 개발한 태양광 집광장치를 식물공장에 적용하여 인공조명과 태양광의 혼합조명장치를 통해 식물을 재배하였다. 그 결과 낮 시간대에 인공조명에 소요되는 전기에너지를 대폭 절감할 수 있었다. 혼합조명장치에서는 조도센서를 활용하여 항상 일정량의 빛이 식물에 제공되도록 LED등의 밝기를 조절하였다. 하루 10시간 기준으로 100형 규모의 식물공장에 태양광 채광시스템을 적용할 경우 한 달에 약 28,080KWh의 에너지 절감효과가 있다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권12호
• /
• pp.624-630
• /
• 2001

The trend of the regulations on environmental issues are getting tight. Responding to this trend new technologies such as moving electrodes, wide pitch and pulsed power supply are also introduced in the electrostatic precipitator(EP) systems. The introduction of wide pitch and moving electrodes enhances the system performance of the EPs by improving air-flow and by improving the ash reentrainment on rapping. The power supplies for the EPs developed up to date include thyristor-based dc or intermittent type, SMPS(switching mode power supply) type and the pulsed-power supply type. The use of the pulsed ones is known to improve dust-collecting efficiency of high resistivity ash and reduces back corona occurrence in the collecting plate. There are two kinds of pulsed-power supplies; one with pulsed transformers and the other with direct dc switching devices. The latter uses rotary spark gap switches or semiconductor switches. Both have the merits and demerits: the spark gap switches are simple and robust but has short life time, hence, high maintenance cost, whereas the semiconductor switches have long life time but are costly. In this study, A high voltage power supply with superimposing voltage pulse on dc source was developed for EPs. This study describes circuit topology, operating principle of the scheme, and analysis of experimental results on Dong-Hae Power Plant. The pulsed power supply consists of a variable dc power supply with ratings of 60kV, 800mA and pulse generator which is made of high voltage thyristor-diode switch strings, an LC resonant tank and a blocking inductor. The pulse generator generates variable pulse-voltage up to 70kV using a high frequency resonant inverter with a variable dc source. Two prototypes were built and tested on 250MW DongHae power plant to verify the possibility of the commercial use and the normal operation in the transient states.

• 로봇학회논문지
• /
• 제7권3호
• /
• pp.171-181
• /
• 2012

Outdoor mobile robots are faced with various terrain types having different characteristics. To run safely and carry out the mission, mobile robot should recognize terrain types, physical and geometric characteristics and so on. It is essential to control appropriate motion for each terrain characteristics. One way to determine the terrain types is to use non-contact sensor data such as vision and laser sensor. Another way is to use contact sensor data such as slope of body, vibration and current of motor that are reaction data from the ground to the tire. In this paper, we presented experimental results on terrain classification using contact sensor data. We made a mobile robot for collecting contact sensor data and collected data from four terrains we chose for experimental terrains. Through analysis of the collecting data, we suggested a new method of terrain feature extraction considering physical characteristics and confirmed that the proposed method can classify the four terrains that we chose for experimental terrains. We can also be confirmed that terrain feature extraction method using Fast Fourier Transform (FFT) typically used in previous studies and the proposed method have similar classification performance through back propagation learning algorithm. However, both methods differ in the amount of data including terrain feature information. So we defined an index determined by the amount of terrain feature information and classification error rate. And the index can evaluate classification efficiency. We compared the results of each method through the index. The comparison showed that our method is more efficient than the existing method.

• 대한전기학회논문지:전력기술부문A
• /
• 제54권4호
• /
• pp.185-192
• /
• 2005

This paper proposes a DRMS(Distribution Remote Management System) which can enhance highly the economics of automatic metering system and the power quality supplied to the electric customer improving the efficiency of the meter reading, voltage management and load management work by realizing the remote meter reading, the remote voltage management and the remote load management based on the ADWHM(Advanced Digital Watt Hour Meter). The DRMS is designed so that the voltage management and load management work in remote site can be processed by collecting the voltage pattern and current pattern as well as watt hour data from all ADWHMs one time every month regularly or from special ADWHMS several time irregularly, A new on-line voltage and load management strategy based on the ADWHM is designed by analyzing the existing voltage management and load management process. Also, DRMS is designed so that watt-hour data, voltage pattern data, load pattern data and power factor data can be collected selectively according to the selection of user to assist effectively the methodology. Remote management program and database of the DRMS are implemented based on Visual C++, MFC and database library of MS. Also, DRMS is designed so as to communicate with the ADWHM using RS232C-TCP/IP converter and ADSL. The effectiveness of the remote metering function is proven by collecting and analyzing the data after ADWHMs installed in any site. The developed strategy and program also is verified through the simulation of voltage management and load management.

• Advances in robotics research
• /
• 제2권3호
• /
• pp.201-217
• /
• 2018

Agriculture production is a critical human intensive task, which takes place in all regions of the world. The process to grow and harvest crops is labor intensive in many countries due to the lack of automation and advanced technology. Much of the difficult, dangerous and dirty labor of crop production can be automated with intelligent and robotic platforms. We propose an intelligent, agent-oriented robotic team, which can enable the process of harvesting, gathering and collecting crops and fruits, of many types, from agricultural fields. This paper describes a novel robotic organization enabling humans, robots and agents to work together for automation of gathering and collection functions. The focus of the research is a model, called HARMS, which can enable Humans, software Agents, Robots, Machines and Sensors to work together indistinguishably. With this model, any capability-based human-like organization can be conceived and modeled, such as in manufacturing or agriculture. In this research, we model, design and implement a technology application of knowledge-based robot-to-robot and human-to-robot collaboration for an agricultural gathering and collection function. The gathering and collection functions were chosen as they are some of the most labor intensive and least automated processes in the process acquisition of agricultural products. The use of robotic organizations can reduce human labor and increase efficiency allowing people to focus on higher level tasks and minimizing the backbreaking tasks of agricultural production in the future. In this work, the HARMS model was applied to three different robotic instances and an integrated test was completed with satisfactory results that show the basic promise of this research.

• 한국ITS학회 논문지
• /
• 제19권6호
• /
• pp.74-87
• /
• 2020

과적차량은 도로 주행환경의 안전을 위협하고 도로구조물의 수명단축에 직접적인 영향을 주는 주요 원인이다. 자중계는 화물차량에 탑재하여 중량을 측정할 수 있는 유일한 장비로, 운전자는 스스로 과적상태를 확인하고 운행 전 상차 시 적재중량을 조절하여 과적을 사전에 예방할 수 있다. 본 연구에서는 과적 적재물 중 골재 및 토사가 전체의 36.55%로 주요 과적적재물로 나타나 이를 주로 운송하는 30대의 건설폐기물 수집·운반차량을 선정하였으며, 자중계의 시범설치 및 원격 모니터링을 수행하여 운행데이터를 수집하였다. 운전자에게 중량을 인지할 수 있는 중량표시 앱을 배포하기 전 1달과 배포한 후 1달 동안 운행데이터를 비교하여 과적 예방효과를 분석하였다. 자중계로부터 제공받은 적재중량을 인지함으로써 과적운행이 6.1%가 감소한 것을 확인하였으며, 운송량을 극대화하면서 단속을 우려하여 원거리로 우회 주행을 할 필요가 없어 운송거리와 시간이 줄어 운송 효율이 높아진 것을 확인하였다.