• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.45-48
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• 2007

COMS satellite is a multipurpose satellite in the geostationary orbit, which accommodates multiple payloads of Meteorological Imager, Geostationary Ocean Color Imager and Ka band Satellite Communication Payload in a single spacecraft platform. In this paper, current status of Korea's first geostationary Communication, Ocean and Meteorological Satellte(COMS) program development is introduced. The satellite platform is based on the Astrium EUROSTAR 3000 communication satellite, but creatively combined with MARS Express satellite platform to accommodate three different payloads efficiently for COMS. The system design difficulties are in the different kinds of payload mission requirements of communication and remote sensing purposes and how to combine them into a single satellite to meet the overall satellite requirements. The COMS satellite critical design has been accomplished successfully to meet three different mission payloads. The platform is in Korea, KARI facility for the system integration and test. The expected launch target of COMS satellite is scheduled in June 2009.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.47-55
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• 2003

This paper Presents active control algorithm using probability density function of structural energy. It is assumed that the structural energy under excitation has Rayleigh probability distribution. This assumption is based on the fact that Rayleigh distribution satisfies the condition that the structural energy is always positive and the occurrence probability of minimum energy is zero. The magnitude of control force is determined by the probability that the structural energy exceeds the specified target critical energy, and the sign of control force is determined by Lyapunov controller design method. Proposed control algorithm shows much reduction of peak responses under seismic excitation compared to LQR controller, and it can consider control force limit in the controller design. Also, chattering problem which sometimes occurs in Lyapunov controller can be avoided.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.100-105
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• 1990

Associated with the protection and control functions in the substations, a new network scheme based on the IEEE 802.4 is proposed in this paper. This network is designed for supporting 3 data classes: 1st, it includes the highly time-critical data for the fault detection function. 2nd, routine data with a period is to served for monitoring the power status. Finally, it contains the control data which is used for reporting an event about protection or tuning some values related with power status. The way to allocate target_token_rotation timer is provided to guarantee the protection and control activities in the suggested network for the substation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1089-1094
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• 2003

A main vibration source in HDD is arisen from high rotating disk/spindle, and vibration suppression of the disk-spindle system becomes a critical issue and a major concern for high performance of the drive. In this paper, we study the feasibility of suppressing unwanted vibration of disk-spindle system of the HDD by external shock and excitation utilizing piezoelectric shunt damping methodology. By considering dynamic characteristics of the disk-spindle system through modal analysis, a target vibration mode is determined and then the piezoelectric material is carefully integrated to the modified drive. In order to maximize improvement of vibration characteristics of the proposed system, shunt circuit is optimally designed via tuning processes. Finally, the vibration characteristics of the high rotating disk-spindle system of the proposed drive is experimentally evaluated in frequency domain.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.10
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• pp.1733-1750
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• 2011

In the early stages of a software project, it is critical to understand the needs of the customers and elicit their customer requirements. Various requirements elicitation methods have been proposed. However, existing methods still have the limitations such as a limited number of target customers, limited expression of customers' opinions, and difficulty in collecting the customers' opinions continuously. A novel method for eliciting customer requirements is proposed by utilizing a social network service (SNS), which is a shared source of raw information of the customers' needs and opinions. The proposed method is validated to show its effectiveness in overcoming the limitations of existing methods.

• Molecules and Cells
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• v.28 no.1
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• pp.7-12
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• 2009

Gliomas, much like other cancers, are composed of a heterogeneous mix of neoplastic and non-neoplastic cells that include both native and recruited cells. There is extensive diversity among the tumor cells, with differing capacity for In vitro and in vivo growth, a property intimately linked to the cell's differentiation status. Those cells that are undifferentiated, self-renewing, with the capacity for developing tumors (tumorigenic) cells are designated by some as cancer stem cells, because of the stem-like properties. These cells may be a critical therapeutic target. However the exact identity and cell(s) of origin of the socalled glioma cancer stem cell remain elusive. Here we review the current understanding of glioma cancer stem cell biology.

• Molecules and Cells
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• v.39 no.12
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• pp.847-854
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• 2016

The early landmark discoveries in cancer metabolism research have uncovered metabolic processes that support rapid proliferation, such as aerobic glycolysis (Warburg effect), glutaminolysis, and increased nucleotide biosynthesis. However, there are limitations to the effectiveness of specifically targeting the metabolic processes which support rapid proliferation. First, as other normal proliferative tissues also share similar metabolic features, they may also be affected by such treatments. Secondly, targeting proliferative metabolism may only target the highly proliferating "bulk tumor" cells and not the slowergrowing, clinically relevant cancer stem cell subpopulations which may be required for an effective cure. An emerging body of research indicates that altered metabolism plays key roles in supporting proliferation-independent functions of cancer such as cell survival within the ischemic and acidic tumor microenvironment, immune system evasion, and maintenance of the cancer stem cell state. As these aspects of cancer cell metabolism are critical for tumor maintenance yet are less likely to be relevant in normal cells, they represent attractive targets for cancer therapy.

• Journal of Korean Society for Quality Management
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• v.27 no.2
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• pp.218-236
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• 1999

The purpose of parameter design is to determine optimal settings of design parameters of a product or a process such that the performance characteristics of a product exhibit small variabilities around their target values. Taguchi made significant contributions in this area. However, his analysis of the problem focused on only one performance characteristic or response, although in product and process design, multiple characteristics are more common. The critical problem in dealing with multiple characteristics is how to compromise the conflict among the selected levels of the design parameters for each individual characteristic. In this paper, Methodology using SN ratio optimized by univariate technique is proposed and a parameter design procedure to achieve the optimal balance among several different response variables is developed. Existing case studies are solved by the proposed method and the results are compared with ones by the sum of SN ratios, the expected weighted loss, the desirability function, and EXTOPSIS model.

• Journal of the Korean Wood Science and Technology
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• v.33 no.2 s.130
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• pp.24-28
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• 2005

Monte Carlo simulation was performed on theoretical models of plywood warp for southern yellow pine plywood originating from the United States. The objective of the investigation was to determine which plywood layers was more warp sensitive to veneers that were manufactured to an undesired thickness. This study found that for a balanced panel (a panel of equal target thickness for each of five layers) manufactured veneers of undesired thickness would experience minimal warp. The veneers of undesired thickness placed in the center of the plywood panel also provided a minimum change of plywood warp properties. The panel warp was very sensitive to surface veneers constructed with undesired thickness. Conversely, this study confirms that monitoring of veneer thickness and proper allocations within the plywood lay-up were critical.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.199-201
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• 2012

본 논문은 함정의 대규모 임무지향시스템에서 전술 데이터를 전송할 때 발생할 수 있는 인코더와 디코더 언더플로우를 방지하고, 트래픽이 프레임 별로 역동적으로 발생할 수 있는 환경을 고려하여 트래픽 스무딩을 수행한 전송 시스템에 대하여 설명한다. 기존의 H.263, H.264의 전송 표준 방식인 on-off policing 방법은 인코더의 목표 비트 전송률(Target Bit Rate)에 따라서 일정한 값으로 정해지는 것과 달리, 프레임을 인코딩함으로써 발생한 프레임의 전체 셀 량과 슬라이스 별로 발생하는 데이터 셀의 역동성을 반영하여 프레임마다 전송시간과 전송률을 반영해주면 부드럽게 전술 데이터의 전송이 일어난다. 또한 기존의 on-off policing과 제시한 대규모 임무지향시스템에서의 트래픽 스무딩 알고리듬의 성능을 비교하여 분석한다.