• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.166-176
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• 2007

Radio frequency (RF) microelectromechanical systems (MEMS) have been pursued for more than a decade as a solution of high-performance on-chip fixed, tunable and reconfigurable circuits. This paper reviews our research work on RF MEMS switches and switching circuits in the past five years. The research work first concentrates on the development of lateral DC-contact switches and capacitive shunt switches. Low insertion loss, high isolation and wide frequency band have been achieved for the two types of switches; then the switches have been integrated with transmission lines to achieve different switching circuits, such as single-pole-multi-throw (SPMT) switching circuits, tunable band-pass filter, tunable band-stop filter and reconfigurable filter circuits. Substrate transfer process and surface planarization process are used to fabricate the above mentioned devices and circuits. The advantages of these two fabrication processes provide great flexibility in developing different types of RF MEMS switches and circuits. The ultimate target is to produce more powerful and sophisticated wireless appliances operating in handsets, base stations, and satellites with low power consumption and cost.

• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.110-118
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• 2011

In this paper, design techniques and technological trends applied on simulator development, which are based on Model Driven Architecture, are described. The methodology, process and modeling support tools for development of simulation software are introduced with both satisfaction of user's requirements and benefit to simulator developers of reducing cost. In addition, contents in ECSS standard for reusability of simulation model and its usages applied on industries are presented and major features of current technological changes with highlights of key-word are discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1065-1066
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• 2008

Printed thin-film transistors (TFTs) have received profound interests as an alternative to their silicon counterparts for use in fabricating next-Gen microelectronics by virtue of projected low manufacturing cost and certain salient features (e.g., thin and lightweight characteristics, structural flexibility, etc.) that printed TFTs bring to device architecture. The economic advantages stem from engaging low-cost printing techniques (e.g., screen printing, gravure, flexography, etc.) for deposition and patterning in place of traditionally costly high-vacuum, high-temperature photolithographic processes. To render printing TFTs possible, solution processable materials are necessary.

• International Journal of High-Rise Buildings
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• v.10 no.1
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• pp.29-34
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• 2021

Vertical greenery has become an important technological means to improve the ecological environment condition in urban high-density areas, especially in central areas of Chinese cities. The cost of vertical greenery has significantly increased both in the decision-making process of architectural design and in the assessment of the sustainability potential of urban complexes. The estimation and evaluation of the cost of vertical greenery have become important obstacles to multi-party investment in the construction of vertical greenery. Considering the factors of the building typology and full life-cycle cost, this paper constructs an assessment model of vertical greenery in seven types in urban complex, and suggests an optimized approach to vertical greenery in an urban complex.

• Journal of the military operations research society of Korea
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• v.3 no.2
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• pp.49-77
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• 1977

Weapon systems are curcial instruments for the security of a nation and critical elements for the victory in a war. Since modern weapon systems tend to be capital-intensive with high precision and quality, they become more and more complex and diversified; their acquisition costs become huge; and their technological obsolescence becomes accelerated. Therefore, the systematic management of weapon acquisition process would be one of the most important defense tasks at the national level. To analyze such problems and find solutions, this paper has studied various aspects related to the efficient management of weapon system acquisition. After brief summarization of the general characteristics of weapon systems, their effectiveness, and developmental trend, the paper discusses the defense management policies and techniques for the weapon systems. Specifically, four alternative acquisition methods such as indigenous R & D, foreign purchase, co-production and joint-production are discussed and analyzed by systems approach. The systems analysis procedure to evaluate and select weapon acquisition method is as follows; 1) to analyze the merits and demerits of the alternative methods, 2) to screen unrealistic alternatives through the consideration of significant factors such as political, economic, military, technological, and social constraints, 3) to evaluate and select an optimal one among the remaining acquisition methods after the cost-effectivenss analysis. For the base of cost-effectivess analysis, cost analysis model as well as effectiveness analysis model of each acquisition method are developed.

• Proceedings of the Safety Management and Science Conference
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• 2013.11a
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• pp.99-104
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• 2013

비용편익분석은 어떤 사업으로 인하여 자연배분의 변화가 생길 때 그에 따른 경제적 편익을 측정하게 되며 사업을 시행하여 생기는 편익과 비용을 비교하여 경제성을 평가하고 대안 중에서 우선순위를 결정할 때 유용하다. 따라서, 본 논문은 자본에 관한 투자기준을 마련하기 위해서 분석용 모델인 "비용편익분석"을 활용 하여 제조기업의 어떤 사업계획에 의하여 생겨나는 자본요소가 어떻게 투자되어야 생산비용을 최소화 할 수 있는지를 자본투자에서 가장 핵심적인 생산설비투자와 기술개발투자에 대한 비용편익분석을 통하여 그 방법론을 제시함으로써, 자본투자에 있어서 "비용효과분석"의 활용성을 확인하고자 한다.

• Journal of Technology Innovation
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• v.13 no.1
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• pp.113-139
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• 2005

The purpose of this study is to analyse the diffusion process of personal computer (PC) in Korea during the 1990's. To achieve the goal, five research steps have been done such as the literature survey of diffusion theory, set-up of theoretic equilibrium model of supply and demand, derivation of an equilibrium path using Hamiltonian, and empirical analysis. The empirical analysis has been performed based on that equilibrium path. The results can be summarized as follows : First, technological attribute of diffusing product influences the diffusion speed of Product. It has been proven that the size of the network has a significant effect on the diffusion of PC in empirical study Second, supply factors have an important role in the diffusion process. According to the empirical analysis, decreasing cost of production as a result of technological advance promotes the speed of diffusion. This point seems to be manifest theoretically, but existing empirical models have not included supply factors explicitly, Third, it has been found out that expectation of decreasing cost would influence the speed of diffusion negatively as expected ex ante. Theoretically this result is supported by arbitrage condition of purchasing timing.

• Structural Engineering and Mechanics
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• v.67 no.6
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• pp.671-682
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• 2018

The effect of earthquake induced torsion, due to mass eccentricities, is investigated with the objective of providing practical design guidelines for minimizing the torsional response of building structures. Current code provisions recommend performing three dimensional static or dynamic analyses, which involve shifting the centers of the floor masses from their nominal positions to what is called an accidental eccentricity. This procedure however may significantly increase the design cost of multistory buildings, due to the numerous possible spatial combinations of mass eccentricities and it is doubtful whether such a cost would be justifiable. This paper addresses this issue on a theoretical basis and investigates the torsional response of asymmetric multistory buildings in relation to their behavior when all floor masses lie on the same vertical line. This approach provides an insight on the overall seismic response of buildings and reveals how the torsional response of a structure is influenced by an arbitrary spatial combination of mass eccentricities. It also provides practical guidelines of how a structural configuration may be designed to sustain minor torsion, which is the main objective of any practicing engineer. A parametric study is presented on 9-story common building types having a mixed-type lateral load resisting system (frames, walls, coupled wall bents) and representative heightwise variations of accidental eccentricities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.140-148
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• 2017

This paper focused on finding a cost-effective LTE mobile network design methodology, suitable for socio-economic circumstances of developing countries. Developing countries have different requirements and circumstances compared with those of developed countries that had deployed LTE networks in advance, thus a differentiated way of design and deployment methods are necessary. This paper analyzed LTE design-related attributes of developing countries, identified relevant technological requirements and appropriate technologies, and suggested design methodologies. These suggestions were verified through the case studies of several developing countries that a Korean telecommunication company (Korean telecom company A) had participated in the LTE design and deployment for future reference by other developing countries.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4933-4956
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• 2016

Use-After-Free (UAF) is a common lethal form of software vulnerability. By using tools such as Web Browser Fuzzing, a large amount of samples containing UAF vulnerabilities can be generated. To evaluate the threat level of vulnerability or to patch the vulnerabilities, automatic deduplication and exploitability determination should be carried out for these samples. There are some problems existing in current methods, including inadequate pertinence, lack of depth and precision of analysis, high time cost, and low accuracy. In this paper, in terms of key dangling pointer and crash context, we analyze four properties of similar samples of UAF vulnerability, explore the method of extracting and calculate clustering eigenvalues from these samples, perform clustering by fast search and find of density peaks on a large number of vulnerability samples. Samples were divided into different UAF vulnerability categories according to the clustering results, and the exploitability of these UAF vulnerabilities was determined by observing the shape of class cluster. Experimental results showed that the approach was applicable to the deduplication and exploitability determination of a large amount of UAF vulnerability samples, with high accuracy and low performance cost.