• Journal of Information Processing Systems
• /
• v.12 no.2
• /
• pp.226-233
• /
• 2016

Cloud computing is a distributed computing model that has lot of drawbacks and faces difficulties. Many new innovative and emerging techniques take advantage of its features. In this paper, we explore the security threats to and Risk Assessments for cloud computing, attack mitigation frameworks, and the risk-based dynamic access control for cloud computing. Common security threats to cloud computing have been explored and these threats are addressed through acceptable measures via governance and effective risk management using a tailored Security Risk Approach. Most existing Threat and Risk Assessment (TRA) schemes for cloud services use a converse thinking approach to develop theoretical solutions for minimizing the risk of security breaches at a minimal cost. In our study, we propose an improved Attack-Defense Tree mechanism designated as iADTree, for solving the TRA problem in cloud computing environments.

• Journal of Korean Institute of Industrial Engineers
• /
• v.14 no.1
• /
• pp.91-101
• /
• 1988

Break-even analysis is a simple and useful tool in decisions and planning activities though its use is somewhat limited to short-term analysis. The subject is discussed in the fields of engineering economics, production management, cost and managerial accounting, finance, marketing, and so on. Conventional break-even analysis suits the case of stable price and low interest rate. In this paper, we try to overcome the limit by considering following factors, namely, time value of money, depreciation, tax, and capital gains. Also, considering learning effect, we increase applicability to a new project which raises certain changes such as a replacement of production process, an employee turnover, etc. Thus, we suggest a model which has a dynamic break-even quantity per period for the project. Furthermore, we examine the effect of inflation in break-even analysis.

• 한국경영정보학회:학술대회논문집
• /
• 2007.11a
• /
• pp.82-87
• /
• 2007

The importance of information technology (IT) has been emphasized in developing countries recently. Despite the importance of the topic area of the productivity of IT in developing countries, the literature to date is relatively sparse. The findings of almost all these studies are based on data collected in developed countries. Few studies have been conducted to validate these results and to see if they are still applicable in developing countries. This study tries to investigate the effects of IT investment on productivity in the electronics industry of China, which is a representative developing country, with production function model. The results show that there is a positive impact of IT investment on productivity in China similar to previous studies in developed countries.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.11
• /
• pp.953-957
• /
• 2001

This paper is concerned with a transfer alignment method for the SDINS under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonliner measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

• International Journal of Aeronautical and Space Sciences
• /
• v.11 no.3
• /
• pp.175-183
• /
• 2010

The increased demand for a higher performing magnetic suspension and balance system (MSBS) resulted in an increase in costs for the efforts necessary for achieving an improved MSBS. Therefore, MSBS performance should be predicted during the design in order to reduce risk. This paper presents the modeling and simulation of an MSBS that controls 6-degree of freedom (DOF) of an aerodynamic body within the MSBS. Permanent magnets and electromagnets were modeled as coils, and this assumption was verified by experimental results. Finally, an MSBS simulator was developed, predicting that the MSBS is able to contain the model within a bounded region as well as measure external forces acting on the body during wind tunnel tests.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.479-482
• /
• 2004

In this article we consider a single maneuvering target Tracking algorithm in the presence of missing measurements and high clutter environments for multi-sensor target tracking problem. The tracking algorithm is based on the Particle filtering method to predict and update target states. Proposed is the AMM-PF(Auxiliary Multiple Model Particle Filter)[2] method for maneuvering target tracking to improve performance in track estimate and maintenance with a high level of uncertainty. The algorithm we propose is compared to the Extended Kalman Filter(EKF). A simulation study is included.

• Journal of electromagnetic engineering and science
• /
• v.18 no.3
• /
• pp.206-211
• /
• 2018

In this paper, we proposed a two-level feature vector fusion technique to improve the performance of target classification. The proposed method combines feature vectors of the early-time region and late-time region in the first-level fusion. In the second-level fusion, we combine the monostatic and bistatic features obtained in the first level. The radar cross section (RCS) of the 3D full-scale model is obtained using the electromagnetic analysis tool FEKO, and then, the feature vector of the target is extracted from it. The feature vector based on the waveform structure is used as the feature vector of the early-time region, while the resonance frequency extracted using the evolutionary programming-based CLEAN algorithm is used as the feature vector of the late-time region. The study results show that the two-level fusion method is better than the one-level fusion method.

• Proceedings of the Korean Information Science Society Conference
• /
• 2011.06b
• /
• pp.67-70
• /
• 2011

정확한 병력수급을 판단하는 것은 병역정책 수립의 근간이 된다. 최근 출산율 감소, 병 복무기간 단축, 국방개혁에 따른 병력규모 변화 등 병력수급에 영향을 미치는 다양한 변수가 증가하여 정확한 병력수급 판단이 더욱 어려워지고 있다. 이러한 가변적인 요소들을 고려하여 잉여/부족 자원 규모를 전망하고 그에 따른 합리적인 인력정책 수립을 지원할 수 있는 병력수급 시뮬레이션 모델 및 시스템을 개발하고 제안하였다. 병력수급 시뮬레이션 모델은 연도별 현역대상자를 판단하는 공급모델과 현역소요를 판단하는 수요모델로 구성되어 있으며, 과부족 판단 결과를 토대로 정책 변수들을 재조정함으로써 여러 가지 대안을 도출할 수 있다. 군내외의 환경 요인은 지속적으로 변화할 것이고, 병력 수급 전망을 통한 적절한 정책 수립의 필요성은 더욱 커질 것이며, 본 시뮬레이션 모델은 합리적인 병역정책 수립 지원에 기여할 것으로 제고된다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.17 no.1
• /
• pp.61-67
• /
• 1999

A watershed terrain factor is known to the very important in studies of a stream and a watershed. We have obtained the terrain factor in map directly or we have generated it in a digitalized map. In this study, DTED (Digital Terrain Elevation Data) offering in DMA(Defense Mapping Agency) was used to create a stream and a watershed and to extract the terrain factor. As comparison of the terrain factors gererated in digitalized map with the terrain factors extracted in DTED, DTED could be used to extract a terrain factor for a watershed management.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1996.11a
• /
• pp.107-116
• /
• 1996

Numerical simulations have been conducted to characterize unsteady flow structures in an axisymmetric supersonic inlet diffuser with sinusoidal pressure oscillations at the diffuser exit. The formulation is based on the unsteady Navier-Stokes equations and turbulence closure is achieved using a two-layer model with a too-Reynolds-number scheme for the near-wall treatment. The governing equations are formulated in an integral form, and are discretized by the four-stage Runge-Kutta scheme for temporal terms and the Harten-Yee upwind TVD scheme for convective terms. Results indicated that the inlet shock characteristics are significantly modified by acoustic oscillations originating from the combustor. The characteristics of shock/boundarv-layer interactions (such as the size of separation bubble, terminal shock shape, and vorticity intensity) are also greatly iufluenced by the shock oscillation due to acoustic waves.