• Journal of electromagnetic engineering and science
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• v.9 no.3
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• pp.118-123
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• 2009

This paper discusses the design and fabrication of a reference signal generator for a naval radar system, including the vibration environment test. The transmit signals of the S-band radar system are synthesized by the reference signal and the phase noise must lower than - 130 dBc/Hz at a 10 kHz offset frequency. To achieve this specification, the phase noise of the reference signal needs to be less than -165 dBc/Hz at a 10 kHz offset. For achieving very low phase noise performance by the reference signal generator, the phase locked loop technique is applied with a 10 Hz loop bandwidth. Also, this reference signal generator has ${\pm}0.35\;ppb$ short-term stability to minimize instant phase errors and high vibration sensitivity against a ship's shaking, unbalanced rotating of antennas and so on.

• Journal of the Korea Institute of Building Construction
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• v.5 no.1 s.15
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• pp.97-103
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• 2005

Building costs means capital costs which include cost of land, costs of acquiring and preparing the site, construction costs, professional fees, furnishings, cost of financing the project. and cost of management required to run and maintenance the building for use. There are several phases that determine the building costs : design phase, construction phase, and operation & maintenance phase. So, the cost of work could be set against the examining the full range of complexities that a building program might contain. To solve this problem, it needs to compute building cost systematically. This is still in the development stage, awaiting the organization of rational cost data base. The method of cost saving by cost control could be constituted by detailed knowledge of building costs for all possible combinations of components and subsystems that can be assembled into integration model of cost factor on each phase of project development. The model of cost saving in each building phase is available for procedures of cost control of building systems.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.19-26
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• 2003

In the face of the deterioration of tobacco manufacturing plant, we've got the plan for now manufacturing factory for the competitiveness, modernization, rationalization and environment. To achieve the goals, it was necessary to plan and investigate in the early stage of project. Consequently. We determined to introduce the CM in the early stage. We Performed the whole phase of CM services front the pre design phase services like feasibility analysis of site and building, plant master plan, selection of manufacturing facilities and drawing up the RFP, to maintenance management phase after the completion of a construction work. Contrary to the another CM projects, YongJu New Tobacco Manufacturing Plant CM organized the CM team with expert in field before the design development. This study analyze and evaluate the CM services of YongJu project which performed on the pre design phase. The purpose of this study is to emphasize the importance of pre design phase CM and support that CM services will start from the pre design phase.

• Archives of design research
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• v.20
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• pp.243-250
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• 1997

In these day, design process has not only visual and industrial departments but also there is an important part which is marketing. Elements of design process are not in accordance with the product and the circumstance of a company but a fundamental role of process is conformed. Moreover, design process is applied in accordance with the character of product and company. In this study, it is based on the concept of home appliances and also can be used in practical work so that there is four stages which are suggested to use for design process. These are planning & visual expression, idea development & expression, presentation & decision and check & control. As a way of development for the management in the design process, firstly, it has to be expressed the identity and the originality of a product, goods and a design strategy. Secondly, product directors should participate in the whole activities of a company, the planning of sales and the process of a design. Thirdly, designers should develop a new communication way so that the manager can be understand easily for a presentation. Finally. it should be systematized to improve the efficiency of design process by introducing various technical management.

• Journal of KIISE:Software and Applications
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• v.30 no.5_6
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• pp.503-514
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• 2003

In conventional development methodologies, requirements are considered to be not changing after analysis phase, and requirements specifications are used for the next step system design purpose. But in the real world, requirements can be changed and modified throughout the development life cycle according to end-user's more understanding about the target system, new IT technologies, changes of customer environment and market situation, and so on. So there needs a requirements change management process that can extend requirements management over the entire development life cycle and can support managing changes to the requirements after design phase. In this paper, a requirements change management process that can be integrated into conventional development methodologies is proposed to support the extension of requirements life cycle and managing changes to the requirements after design phase. This process was evaluated through an verification test with a widely used development methodology‘MaRMI’.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.9
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• pp.787-798
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• 2015

The emergence of mid-to-small satellites has created a need for rapid development with a relatively low cost. However, the development of mid-to-small satellites requires considerable time and cost in early phase, in particular, during the development of mission and system requirements through iterations of conceptual design and mission design. In this research, Spacecraft Conceptual Design Tool(SCDT) which is based on Graphical User Interface(GUI) was developed to reduce the time and cost for early phase development. Furthermore, GUI-based software can make the input values to be editable easily and show users design results in various way. In this paper, the development results of MATLAB GUI-based SCDT are introduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.4
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• pp.325-334
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• 1987

Microwave integrated circuit phase shifters have undergone remarkable development to satisfy the fast and precise phase control requirements for phased array antennas. It is shown how relection type phase shift circuits using PIN diode can be analyzed and implemented so as to derve design equations for any phase shift. The reflection properties are achieved by the use of an impedance transforming two-port network and the virtual matching impedance method. Experimental and theoretical performance of 2-bit hybrid phase shifter designed by this method are found to be in good agreement for each bit.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.416-421
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• 2005

Most of solar system dissemination has been focused on domestic hot water system of which utilization to a building is relatively simple and safe than solar heating system. Through the survey on a cause of solar house dissemination failure in Korea, we conclude that design integration and systematic approach method for technology application are the most important element for a successful solar house. KIER(Korea Institute of Energy Research) and Hanbat National University have started new project on a development of Zero energy Solar House, called ZeSH which can be sustained just by natural energy without the support of existing fossil fuel. This is the 1st phase research of 10 years long-term ZeSH plan which develops a low-cost and $100\%$ self sufficient ZeSH. The goal of 1st phase ZeSH research is to get a $70\%$ self sufficiency only in thermal loads. Actual demonstration house, named KIER ZeSH I was designed and constructed as a result of 1st phase research work in the end of 2002. Various innovative technologies such as super insulation, high performance window, passive and active solar systems, ventilation heat recovery system are applied and evaluated to the KIER ZeSH I. A lot of computer simulations had been conducted for the optimal design and system integration in every design steps. Considering all the results from detailed hourly computer simulation, it is expected that at least $70\%$ self-sufficiency in thermal loads which is 1st phase target value can be excessively achieved in actual demonstration house. Besides, many valuable findings from the design and analysis to construction could be established such as collaboration method among the participants, practical design and construction techniques for system integration and the others. The purpose of this paper is to introduce the main findings through the development of KIER ZeSH I project. Practical guidelines in every design step for new low- or zero- energy solar house is proposed as result.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.370-379
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• 2015

Handling constantly evolving configurations of aircraft can be inefficient and frustrating to design engineers, especially true in the early design phase when many design parameters are changeable throughout trade-off studies. In this paper, a physics-based design framework using parametric modeling is introduced, which is designated as DIAMOND/AIRCRAFT and developed for structural design of transport aircraft in the conceptual and preliminary design phase. DIAMOND/AIRCRAFT can relieve the burden of labor-intensive and time-consuming configuration changes with powerful parametric modeling techniques that can manipulate ever-changing geometric parameters for external layout of design alternatives. Furthermore, the design framework is capable of generating FE model in an automated fashion based on the internal structural layout, basically a set of design parameters describing the structural members in terms of their physical properties such as location, spacing and quantities. The design framework performs structural sizing using the FE model including both primary and secondary structural levels. This physics-based approach improves the accuracy of weight estimation significantly as compared with empirical methods. In this study, combining a physics-based model with parameter modeling techniques delivers a high-fidelity design framework, remarkably expediting otherwise slow and tedious design process of the early design phase.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.183-186
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• 1999

The Ultra-miniature and low phase noise Colpitts VCO of 0.06㏄ in size has been developed using the high Q resonator and phase compensation technique. This type is one transistor VCO without a buffer. To design and simulate the VCO accurately, nolinear model parameters of a bipolar transistor are extracted using the measured I-V data and S parameters based on the Gummel-Poon model. Design and simulation have been done by Serenade 7.5 design tool using the extracted nonlinear model parameters. The wideband VCO has been designed using two varactor diodes and open loop gain compensation technique to improve the operating frequency range. The ultra-miniature VCO has shown the phase noise of -91㏈c/Hz at 10KHz offset and output power of -3㏈m The wideband VCO has shown the tuning frequency bandwidth of 150MHz phase noise of -95㏈c/Hz at 10KHz offset and output power of 5㏈m.