• The Journal of Fisheries Business Administration
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• v.46 no.3
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• pp.83-101
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• 2015

The main purpose of this study is to explore a way of South-North Korea fisheries cooperation through international organizations under the principles of the Korean peninsula trust process. Considering the government policy toward the North, although some humanitarian aids or cooperations may be plausible with permission of the Ministry of Reunification. direct cooperations between the South and the North Korea must be much limited at leat under the present government. The 5.24 measures taken in 2010 banned in fact all economic/humanitarian cooperations by private sectors and government. Noting the present and the visible future, an important question is whether the North accepts all cooperations including fisheries, bartering giving up nuclear weapon development for the 5.24 measures. It would be a difficult question to be answered, because win-set to both parties is too narrow, so far as there is no change in the South-North conflicting priority policies. If so, one way of implementing South-North fisheries cooperations is to drive forward cooperative programs through UN organizations. Since for instance FAO and WFP secure justification and roles and has a global network, they have sufficient capacity of being abe to organize fisheries experts. If the South can finance the budget necessary for the programs, FAO or WFP would lead the programs through a negotiation with the North. In other words, it is a type of cooperative model that FAO or WFP leads the programs and the South finances. In addition, if World Fisheries University(WFU) is invited to the Republic of Korea, it might make a great contribution to expert exchange of the North.

• Spatial Information Research
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• v.5 no.2
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• pp.185-194
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• 1997

Spatial decision support systems(SDffi), a new class of decision support system(DSS), result from the melding together of GIS and DSS, Planning support systems(PS5) add more advanced spatial analysis functions than GIS and intertemporal functions to the functions of SDSS. This paper reports the development of a planning support system providing a framework that facilitates urban planners and civil engineers in conducting coherent deliberations about the generation of satisficing sewers. 1he planning support system for the generation of satisficing sewers(PS5/GSS) was designed from the understanding that land use and development drive the demand for storm and sanitary sewers. Through four stages of supply, demand, alternative generation, and evaluation, PSS/GSS integrates basic planning, preliminary design, and engineering design of sewer. GIS and graphic user interface are excellent toolboxes for designing sewer networks, estimating the quantity of wastewater, and showing generated alternative sewers. A sewer model using simulation tedmique can generate an initial sewer. Users can define alternative sewers by the direct manipulation of sewer networks or by the manipulation of parameters in the sewer model. The sewer model evaluates the performance of the user defined alternatives.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1743-1750
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• 2003

DC motor requires a rotor speed sensor for accurate speed control. The speed sensors such as resolvers and encoders are used as a speed detector, but they increase cost and size of the motor and restrict the industrial drive applications. So in these days, many papers have reported in the sensorless operation of DC motor〔3­5〕. This paper presents a new sensorless strategy using neural networks〔6­8〕. Neural network has three layers which are input layer, hidden layer and output layer. The optimal neural network structure was tracked down by trial and error, and it was found that 4­16­1 neural network structure has given suitable results for the instantaneous rotor speed. Also, learning method is very important in neural network. Supervised learning methods〔8〕 are typically used to train the neural network for learning the input/output pattern presented. The back­propagation technique adjusts the neural network weights during training. The rotor speed is gained by weights and four inputs to the neural network. The experimental results were found satisfactory in both the independency on machine parameters and the insensitivity to the load condition.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.187-190
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• 2002

In contrast to conventional electromagnetic motor, USM(Ultrasonic Motor), as piezoelectric ceramic applying ultrasonic mechanical vibration and as frictional-movement type motor, get rotational torque by elastic friction between stator and rotator, The USM, which is small motor without iron cores and coil as a simple structure, has little load weight, has character of high torque at low speed, and can apply a direct drive type without deceleration gear as low speed type. A response of USM from control input is satisfactory, and also generates much torque in low speed driving, and holding torque is much without supplying power. In this study, I designed and made Ultrasonic motor-digital multi controller(USM- DMC) using FPGA chip, A54SX72A made in Actel Corporation. By the minute, USM-DMC can control frequency, duty ratio, and phase difference of USM by llbit digital input from Pc. Therefore, when we use this controller, we can apply to typical parameter, frequency, phase difference, and voltage parameter, to control as well as we can do mixing control like phase-frequency, phase-voltage, frequency-voltage, frequency-phase-voltage, What is more, the strongest point is that it can trace frequency based on optimized frequency because we can input optimized resonant frequency while in motoring.

• Tribology and Lubricants
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• v.22 no.2
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• pp.59-65
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• 2006

In hard disk drives as the head to disk spacing continues to decrease to facilitate recording densities, slider disk interactions have become much more severe due to direct contact of head and disk surfaces in both start/stop and flying cases. The slider disk interaction in CSS (contact-start-stop) mode is an important source of particle generation and tribocharge build-up. The tribocharge build-up in the slider disk interface can cause ESD (electrostatic discharge) damage. In turn, ESD can cause severe melting damage to MR or GMR heads. The spindle speed of typical hard disk drives has increased in recent years from 5400 rpm to 15000 rpm and even higher speeds are anticipated in the near future. And the increasing disk velocity leads to increasing disk acceleration and this might affect the tribocharging phenomena of the slider/disk interface. We investigated the tribocurrent/voltage build-up generated in HDD, operating at increasing disk accelerations. In addition, we examined the effects with relative humidity conditions and rest time. We found that the tribocurrent/voltage was generated during pico-slider/disk interaction and its level was about $3\sim16pA$ and $0.1\sim0.3V$, respectively. Tribocurrent/voltage build-up was reduced with increasing disk acceleration. Higher humidity conditions $(75\sim80%)$ produced lower levels tribovoltage/current. Therefore, a higher tribocharge is expected at a lower disk acceleration and lower relative humidity condition. Rest time affected the charge build-up at the slider-disk interface. The degree of tribocharge build-up increased with increasing rest time.

• Journal of The Korean Astronomical Society
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• v.51 no.6
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• pp.207-214
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• 2018

A coelostat is often used for solar observations, because it corrects the image rotation automatically by guiding sunlight into a fixed telescope with two plane mirrors. For the purposes of education and spectroscopic observation, the solar group at Seoul National University (SNU) plans to develop the SNU coelostat (SNUC) and install it in the SNU Astronomical Observatory (SAO). Requirements of the SNUC are < 1" positioning accuracy with 30 cm beam size on the entrance pupil in the compact dome. To allow for installation in the small dome, we design a compact slope type coelostat with a 45 cm primary plane mirror and a 39 cm secondary plane mirror. The motion of the SNUC is minimized by fixing the position of the slope frame. Numerical simulations of the available observational time of the designed coelostat shows that the sun can be observed ay all times from June to early August and at least three hours in other months. Since the high accuracy driving motors installed in the SNUC can be affected by external environment factors such as humidity and temperature variations, we design a prototype to test the significance of these effects. The prototype consists of a 20 cm primary plane mirror, a 1 m slope rail, a direct drive motor, a ballscrew, a linear motion guide, an AC servo motor, a reduction gear and a linear encoder. We plan to control and test the accuracy of the prototype with varying atmospheric conditions in early 2019. After testing the prototype, the SNUC will be manufactured and installed in SAO by 2020.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.59-65
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• 2019

In this study, optimal design of direct-drive VCMs (Voice Coil Motor) for a missile fin actuator is carried out. The torque performance and the characteristics of the VCM are predicted by commercial electromagnetic analysis software, ANSYS Maxwell. The optimal design is obtained at the minimum and maximum actuating angles where the aerodynamic load acting on the fin is the largest in the operating range. The critical variables of the actuator is designed and the RSM (Response Surface Method) is used for the optimization. The response surface model consists of second-order functions and its experimental points are selected by a central composite design. This design is widely used for fitting a second-order response surface. The adjustment regression coefficients is computed for adequacy checking of the response surface model. Finally, the torque values obtained by the RSM and the ANSYS Maxwell are shown in good agreement.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.467-472
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• 2020

The superconducting synchronous generator is one of the breakthrough elements for direct-drive wind turbines because it is light and small. Normally the superconducting one has copper armature windings in the stator and superconducting field windings on the rotor. The high resistance of the armature can make large copper losses, comparing with the conventional generators with a gear box. One of the solutions for the large copper losses could be a fully superconducting generator. But the high magnetic fields from the superconducting field windings on the rotor also make high perpendicular magnetic fields on the superconducting tapes in the armature windings. We have proposed a fully superconducting synchronous generator with dual field windings. It could immensely decrease the circumferential component of the magnetic field from the field windings at the armature windings. In this paper, we conceptually designed 3 types of superconducting synchronous generators. The first one is the fully superconducting one with conventional structure, which has superconducting armature windings in the stator and superconducting field windings on the rotor. The second one is the one with dual superconducting field windings and superconducting armature windings between them. The last one is the same as the third one except the structure of the armature. If the concentrated armature windings are superconducting ones with cryostats, then they cannot be installed within the span of 2 poles. So, we adopted 3 phases windings within 4 poles system. It makes more AC losses but can be manufactured really.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.345-353
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• 2009

The success and failure of any project depends upon many factors, the Project Manager is considered to be the key contributor to the success of any project, as well as a guide to the team members to achieve the client satisfaction (Cost, Time and Quality). Therefore the main aim of this paper is to provide a practical approach for understanding the importance of the Project Manager and his effectiveness to the success of the construction projects. In addition, the Project Manager's roles, responsibilities and duties have direct impact to the success of the construction projects. In order to identify the thoughts and opinion of the construction industry on this particular assertion, a quantitative study was carried out within the UK construction industry. The result of the study shows that there is an extremely strong correlation between the Project Manager and the success of the construction projects. In construction projects the Project Manager is considered to be one of the most important people who can lead and drive the projects in the right direction and conclude construction projects successfully. Moreover, these can play the most important role regarding the improvement of the organization's performance, the organization's profitability and the client's satisfaction. The research confirmed that the Project Manager is a very essential element to the success of the construction project and have an impact at every stage of the construction project. So it concluded that selection of a Project Manager should be carefully done with regard to experience, knowledge, power/authority and good understanding to the kind of the project.

• Archives of design research
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• v.13
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• pp.153-162
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• 1996

The residence space has been in the trend of being expanded with the J'l'cent economic growth Therefore PAC may be said to have [wen from business use to home US(: the progressed living standard as the goods ior Uw "ummel' S('dSOn rest'ntly though sold in Uw fast for mainly buslTw"s use. PAC has been in the demand day ;lner day and in the tn'nd on the bc,ing the necessJty of the n'sent wf',lther warming phenomenon This study is the case study nf the products development and design process of PAC which has bpcn llrivcn and developed by Gold Star Co. ,Ltd. Which .is the firm for home electric appliances representing Korea. This studies for the development and the design of the products by the firm thus emphasizing the visulizing it based on this study. For example as they being the goods for the summer season I have tried to know the physical quakity and the characters of koreans by the weather conditions and estimated the demand by setting up the target customers of the PAC as the customers' environment. And I analyzed the acts in the living room in the apartments as the living envinorment which has the direct relation with PAC and also became a help to the moulding work of PAC by analyzing the complete interior image in the living room. In the practical moulding work the Design concept was classified into the envinorment of customer, living and products to drive as the below. Firstly - New shape (Round slim) has been realized which leads the minimizing the moulding space and visul sense of opening as its being spacious. The 2nd - the high class sense of the products which are harmonious with the atmosphere of the living room by making it interiorized has been visible. The 3rd - The shape stimulating the sensitivity of the users and surface treatment are emphasized by making it be touched. The 4th - During inviting use of technology image which appears in the electronics products are attemptedby making it be high quality.king it be high quality.