• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.2 no.4
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• pp.1-17
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• 2007

There are many different types of risk capital competing for deals in the korean entrepreneurial capital market. In the past, even though korean private venture capitalists did not have their distinctive competitive advantages, due to government support and subsidies, they could be survived in the market. However, the government controlled area has changed to a market driven area which emphasizes market forces and competition rather than support and protection. In order to be competitive, Korean private venture capital firms need to recruit high calibre professionals and build required financial skills for wise entrepreneurial investments. The purpose of this article is to analyze the relationships among firm characteristics, human resources, and investment strategies of korean venture capital firms. We can find that the asset size of venture capital firms has a positive effect on the size of their human resources. However, we can not find any relationship between firm characteristics and investment strategies of venture capitals. Even though we find some evidences among some variables, we need to interpret the results very carefully. Further research would be needed to carried out to clarify the disputable interpretations and our understanding of this area.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.36-44
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• 2015

This paper proposes a low-complexity processor to correct vignetting and barrel distortion for wide-angle cameras. The proposed processor calculates the required correcting factors by employing the piecewise linear approximation so that the hardware complexity can be reduced significantly while maintaining correction quality. In addition, the processor is designed to correct the two distortions concurrently in a singular pipeline, which reduces the overall complexity. The proposed processor is implemented with 18.6K logic gates in a $0.11{\mu}m$ CMOS process and shows the maximum correction speed of 200Mpixels/s for correcting an image of which size is $2048{\times}2048$.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.30-37
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• 2012

A memory system with the linear skewing scheme has been regarded as one of suitable memory systems for a single instruction, multiple data (SIMD) architecture. The memory system supports simultaneous access n data to m memory modules within various access types with a constant interval in an arbitrary position in two dimensional data array of $M{\times}N$. Although $m{\times}cells$ memory cells are physically required to support logical two dimensional $M{\times}N$ array of data by means of the memory system, at least (m-n)${\times}cells$ memory cells remain in disuse, where cells is (M-1)/q+(N-1)/$p{\times}{\lceil}M/q{\rceil}+1$. On keeping functionalities the memory system supports, $(n{\times}t){\times}N/p$ out of a number of unused memory cells, where t>0, being used as local buffer memories for n processing elements is proposed in this paper.

• Journal of Korea Multimedia Society
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• v.11 no.8
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• pp.1093-1100
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• 2008

Feistel and SPN are the two main structures in designing a block cipher algorithm. Unlike Feistel, an SPN has an asymmetric structure in encryption and decryption. In this paper we propose an SPN algorithm which has a symmetric structure in encryption and decryption. The whole operations in our SPN algorithm are composed of the even numbers of N rounds where the first half of them, 1 to N/2, applies function and the last half of them, (N+1)/2 to N, employs inverse function. Symmetry layer is executed to create a symmetry block in between function layer and inverse function layer. AES encryption and decryption algorithm, whose safety is already proved, are exploited for function and inverse function, respectively. In order to be secure enough against the byte or word unit-based attacks, 32bit rotation and simple logical operations are performed in symmetry layer. Due to the simplicity of the proposed encryption and decryption algorithm in hardware configuration, the proposed algorithm is believed to construct a safe and efficient cipher in Smart Card and RFID environments where electronic chips are built in.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.247-250
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• 2008

RC6 which has different algorithm of encryption and decryption has been implemented to have the same algorithm between encryption' and decryption though inserting symmetry layer using simple rotate and logical operation. That means the half of whole RC6 round uses encryption algorithm and the rest of it uses decryption one and symmetry layer has been put into the middle of encryption and decryption. The proposed RC6 algorithm has no difference with the original one in the speed of process. However it is quite safe because by inserting symmetry layer the path of high probability which is needed for differential and linear analysis is cut oft so that it is hard to be analyzed. The proposed algorithm can be easily applied to the algorithm which has different encryption and decryption an make it same, and it can be good idea to be used to design a new block cipher algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10C
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• pp.1025-1031
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• 2007

This paper proposes an area-efficient pipeline FFT processor for MIMO-OFDM systems with four transmitting and four receiving antennas. Since the MIMO-OFDM system transmits multiple data streams, the complexity for the MIMO-OFDM system with a single-channel FFT processor increases linearly with the increase of the number of transmit channels. The proposed FFT processor is based on multi-channel structure, and therefore it can efficiently support multiple data streams. With the mixed radix algorithm, the number of non-trivial multiplications of the proposed FFT processor is decreased. The proposed FFT processor is synthesized with CMOS $0.18{\mu}m$ process and reduces the logic gates by 25% over a 4-channel Radix-4 multi-path delay commutator (R4MDC) FFT processor. Since the MIMO-OFDM FFT processor is one of the largest modules in the systems, the proposed FFT processor will be a vast contribution improvement to the low complexity design of MIMO-OFDM systems.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.11
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• pp.995-1004
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• 2011

Object X-ray method commonly used for hole search in overset grids requires huge amount of time due to complicated vector calculations to search the cross-points as well as time-consuming hole search algorithm with respect to background grids. Especially, when the grid system is in motion relative to the background, hole points should be searched at every time step, leading to hung computational burden. To cope with this difficulties, this study presents an efficient hole search algorithm mainly designed to reduce hole searching time. To this end, virtual surface with reduced grid points is suggested and logical operators are employed as a classification algorithm instead of complicated vector calculations. In addition, the searching process is further accelerated by designating hole points in a row rather than discriminating hole points with respect to each background grid points. If there exists a relative motion, the present algorithm requires much less time because only the virtual surface needs to be moved at every time step. The hole searching time has been systematically compared for a few selected geometries.

• Spatial Information Research
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• v.14 no.2 s.37
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• pp.245-260
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• 2006

A practical use of the location information and user requirement are increased in a mobile environment which supports the portability. And Various service which GIS is related with a Spatial DB have been processed. Generally, logical relation of a traffic network which organizes the Road DB uses a basic node-link structure. In this way, Designed structure can not be flexible at various model apply and are not efficient with a database retrieval in a maintenance management side. In this research, We supplement with the problem of a existing network model and the limitation of the building through the design of a network model which uses dynamic segmentation. And we tried to implement efficient hierarchy model at the retrieval of the network and presentation. Designed model supports a stage presentation of various level and a hierarchy entity relation and We are expected to supplement a network spatial modelling function which the GIS has.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.952-958
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• 1999

This paper presented the application of GAs as a means of finding optimal solutions over a parameter space in the controller design for a fuzzy control system. The performance can involve a weighted combination of various performance characteristics such as rise-time, settling-time, settling-time, overshoot. The results obtained here are compared with those for a traditional design obtained using the root-locus method. In contrast to traditional methods, the GA-based method does not require the usual mathematical processess or mathematical model of the system. In this paper, the Ga-based Fuzzy control system combining Fuzzy control theory with the GA, that is known to be very effective in the optimization problem, will be proposed The effectiveness of the proposed control system will be demonstrated by computer simulations using task tracking position system in stable and unstable linear systems. It is shown that the GA-based controller is better than the traditional controller used It stable and unstable linear systems.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.7-15
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• 2005

Numerical analysis model is proposed to predict the dynamic behavior of a single-degree-of-freedom structure that is equipped with hybrid base isolation system. Hybrid base isolation system is composed of friction pendulum systems (FPS) and a magnetorheological (MR) damper. A neuro-fuzzy model is used to represent dynamic behavior of the MR damper. Fuzzy model of the MR damper is trained by ANFIS (Adaptive Neuro-Fuzzy Inference System) using various displacement, velocity, and voltage combinations that are obtained from a series of performance tests. Modelling of the FPS is carried out with a nonlinear analytical equation that is derived in this study and neuro-fuzzy training. Fuzzy logic controller is employed to control the command voltage that is sent to MR damper. The dynamic responses of experimental structure subjected to various earthquake excitations are compared with numerically simulated results using neuro-fuzzy modeling method. Numerical simulation using neuro-fuzzy models of the MR damper and FPS predict response of the hybrid base isolation system very well.