• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.357-358
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• 2006

전력 산업이 자유화되고 경쟁을 통해 효율성을 증가시키려는 시도가 이루어지고 있다. 전력이 시장을 통해 거래되는 형태가 완전경쟁에 가까울수록 사회후생이 증가한다는 것이 알려져 있다. 하지만 발전 회사가 시장지배력을 행사하여 가격을 경쟁가격에서 벗어나게 함으로서 자신의 이익을 취하려 할 때 시장의 효율성은 감소하게 된다. 시장 지배력을 감소시키는 한 수단으로서 발전회사에 선도계약을 부과하는 방법이 있다. 발전 회사에 선도계약을 부과하는 방법을 사용할 때 어떤 회사를 선도계약 부과대상으로 삼을 것 인지와 계통의 송전제약 통에 대한 고려가 필요하다. 이에 대한 연구가 2모선 계통에 대해 게임이론의 혼합균형 개념을 통해 부분적으로 이루어져 있다. 본 논문에서는 3모선 계통에서 선도계약의 영향을 분석하고자 한다. 본 논문의 해석 결과에 의하면 3모선 계통에서도 선도계약은 상황에 따라 시장지배력의 감소 혹은 증가를 모두 불러올 수 있으며 기대사회후생에 부정적 영향 뿐 아니라 부정적 영향 역시 줄 수 있다.

• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.461-470
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• 2010

Semi supervised classification which is a method using labeled and unlabeled data has considerable attention in recent years. Among various methods the graph based manifold regularization is proved to be an attractive method. Least squares support vector machine is gaining a lot of popularities in analyzing nonlinear data. We propose a semi supervised classification algorithm using the least squares support vector machines. The proposed algorithm is based on the manifold regularization. In this paper we show that the proposed method can use unlabeled data efficiently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.755-761
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• 2005

In this paper, we proposed a channel estimation method by impulse signal train in OFDM. In order to estimate the channel response, 4 impulse signals are generated and transmitted during one OFDM (Orthogonal Frequency Division Multiplexing) symbol. The intervals between the impulse signals are all equal in time domain. At the receiver, the impulse response signals are summed and averaged. And then, the averaged impulse response signal is zero padded and fast Fourier transformed to obtain the channel estimation. The BER performance of the proposed method is compared with those of conventional estimation method using the long training sequence in fast fading environments. The simulation results show that the proposed method improves by 3 dB in terms of Eb/No, compared with the conventional method.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.185-195
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• 2011

Aircraft-related accidents cause mass casualties and major material damages. At present, runway-related accidents in our country account for 28% of all air accidents. Furthermore, internationally 33% of all air accidents is connected with runway. To prevent these accidents, FAA mandates the installation of aircraft rapid arresting system(ARAS) at the runway end safety areas which do not meet the FAA requirements. Even if the areas satisfy the conditions, FAA recommends the installation of ARAS to ensure the safety. In accordance of the international affairs, the domestic studies for ARAS are in progress and the legal formalities for domestic adoption of ARAS is under way. In this study, we analyzed the stopping distance, drag force, vertical force and tire penetration of runway overrun to assess the performance of ARAS reasonably by using two different kinds of analysis programs. The first is ARRESTOR program adopted by FAA, and the second is LS-DYNA which is available for 3-dimensional nonlineal dynamic analysis. As a result, analytically the stopping distances between two programs are similar. The drag force is rather different, but the tendencies are similar. Later on, the 3-dimensional simulation analysis considering various air-craft condition and properties of packaging materials is necessary. In addition, ongoing development of simulation analysis program is required for more accurate analistic results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.5
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• pp.343-349
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• 2013

Crashworthy fuel cells have a great influence on improving the survivability of crews. Since 1960's, the US army has developed a detailed military specification, MIL-DTL-27422, defining the performance requirements for rotorcraft fuel cells. In the qualification tests required by MIL-DTL-27422, the crash impact test should be conducted to verify the crashworthiness of fuel cell. Success of the crash impact test means the improvement of survivability of crews by preventing post-crash fire. But, there is a big risk of failure due to huge external load in the crash impact test. Because the crash impact test itself takes a long-term preparation efforts together with costly fuel cell specimens, the failure of crash impact test can result in serious delay of a entire rotorcraft development. Thus, the numerical simulations of the crash impact test has been required at the early design stage to minimize the possibility of trial-and-error with full-scale fuel cells. Present study performs the numerical simulation using SPH(smoothed particle hydro-dynamic) method supported by a crash simulation software, LS-DYNA. Test condition of MIL-DTL-27422 is reflected on analysis and material data is acquired by specimen test of fuel cell material. As a result, the resulting equivalent stresses of fuel cell itself are calculated and vulnerable areas are also evaluated.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.66-78
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• 2015

With the development of bio computing technology, DNA watermarking to do as a medium of DNA information has been researched in the latest time. However, DNA information is very important in biologic function unlikely multimedia data. Therefore, the reversible DNA watermarking is required for the host DNA information to be perfectively recovered. This paper presents a reversible DNA watermarking using least square based prediction error expansion for noncodng DNA sequence. Our method has three features. The first thing is to encode the character string (A,T,C,G) of nucleotide bases in noncoding region to integer code values by grouping n nucleotide bases. The second thing is to expand the prediction error based on least square (LS) as much as the expandable bits. The last thing is to prevent the false start codon using the comparison searching of adjacent watermarked code values. Experimental results verified that our method has more high embedding capacity than conventional methods and mean prediction method and also makes the prevention of false start codon and the preservation of amino acids.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.269-274
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• 2007

This experiment was conducted to determine the effect of seeding method on winter survival and dry matter yield of Italian ryegrass(Lolium multiflorum Lam. "Kospeed") in paddy field for two years. The experiment was arranged in randomized complete block design with three replications. The treatment consisted of four different seeding methods, R-LS-P(rotary-line sowing-packing), R-BS-P(rotary-broadcast seeding-packing), R-BS(rotary-broadcast seeding), R-BS-TR(rotary-broadcast seeding-trifling rotary), BS-TR(broadcast seeding-trifling rotary). The emergence ratio of broadcast was decreased by 12% and winter survival was decreased by 17% compared with line sowing. The R-BS-TR treatment which was practical seeding method of rye was decreased seeding stand ratio by 65.2% and winter survival by 6.7% compared with others seeding methods. Dry matter yield of line sowing(8,151 kg/ha) was higher than that of broadcast(6,281 kg/ha) and R-BS-P treatment was the highest DM yield as 7,166 kg/ha. There was not found significant difference among seeding method in forage quality. The results of this experiment indicated that R-BS-P(rotary-broadcast seeding-packing) was recommendable the best seeding method after harvested whole crop rice in paddy field.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.123-130
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• 2007

The aim of this study was to propose a fusion and registration method with heterogeneous small animal acquisition system in small animal in-vivo study. After an intravenous injection of $^{18}F$-FDG through tail vain and 60 min delay for uptake, mouse was placed on an acryl plate with fiducial markers that were made for fusion between small animal PET (microPET R4, Concorde Microsystems, Knoxville TN) and Discovery LS CT images. The acquired emission list-mode data was sorted to temporally framed sinograms and reconstructed using FORE rebining and 2D-OSEM algorithms without correction of attenuation and scatter. After PET imaging, CT images were acquired by mean of a clinical PET/CT with high-resolution mode. The microPET and CT images were fusion and co-registered using the fiducial markers and segmented lung region in both data sets to perform a point-based rigid co-registration. This method improves the quantitative accuracy and interpretation of the tracer.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.67-72
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• 2007

An efficient method for identification of MIMO state space model has been developed by combining partial least squares (PLS) regression, balanced realization, and balanced truncation. In the developed method, a MIMO system is decomposed into multiple MISO systems each of which is represented by a high-order ARX model and the parameters of the ARX models are estimated by PLS. Then, MISO state space models for respective MISO ARX transfer function are found through realization and combined to a MIMO state space model. Finally, a minimal balanced MIMO state space model is obtained through balanced realization and truncation. The proposed method was applied to the design of model predictive control for temperature control of a high pressure $CO_2$ solubility measurement system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1081-1086
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• 2012

This study deals with hardness evaluation for spot welding by using an instrumented indentation technique to improve the quality of the inspection methodology. First, an instrumented indentation test and a Rockwell hardness test were performed for normal and abnormal spot welding. The hardness to indentation force-displacement curve obtained using each of the tests was compared. Furthermore, an analysis was conducted using the hardness obtained by the instrumented indentation technique. A quality control standard based on reliability was this evaluated for spot welding.