• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.7
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• pp.22-29
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• 2002

The Gauranteed Frame Rate service category was proposed by the ATM Forum as an enhancement to the UBR service. This service aims to support minimum cell rate gaurantee for each virtual connection and allow any excess bandwidth in the network to be shared among the contending VCs in a fair manner. We propose a new buffer management algorithm for GFR service through FIFO queuing discipline. Proposed scheme can provide minimum bandwidth guarantee for GFR VCs as well as improve the fairness among the competing GFR VCs on a single FIFO queue. From simulation results, we demonstrate the proposed scheme fulfills the requirement of GFR service as well as improves the TCP throughput.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.238-244
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• 2007

Guaranteed Frame Rate(GFR), recently approved by the ATM Forum, expects to become an important service category to efficiently support TCP/IP traffic in ATM networks. The GFR service not only guarantees a minimum service rate at the frame level, but also supports a fair share of available bandwidth. We proposed new scheduling scheme for the GFR service. Proposed scheme provides priority to VCs and high priority to a VC which have more untagged cells in buffer. High priority VCs have much more serviced than low priority. Proposed scheme can provide MCR(minimum cell rate) guarantee and fair sharing to GFR VCs. Computer simulation results show that proposed scheduling scheme provide a much better performance in TCP goodput and fairness than previous scheme.

• Journal of Astronomy and Space Sciences
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• v.26 no.4
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• pp.567-588
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• 2009

Korea-Japan Joint VLBI Correlator (KJJVC) is being developed by collaborating KASI (Korea Astronomy and Space Science Institute), Korea, and NAOJ(National Observatory of Japan), Japan. In early 2010, KJJVC will work in normal operation. In this study, we developed the software correlator which is based on VCS (VLBI Correlation Subsystem) hardware specification as the core component of KJJVC. The main specification of software correlator is 8 Gbps, 8192 output channels, and 262,144-points FFT (Fast Fourier Transform) function same as VCS. And the functional algorithm which is same as specification of VCS and arithmetic register are adopted in this software correlator. To verify the performance of developed software correlator, the correlation experiments were carried out using the spectral line and continuum sources which were observed by VERA (VLBI Exploration of Radio Astrometry), NAOJ. And the experimental results were compared to the output of Mitaka FX correlator by referring spectrum shape, phase rate, and fringe detection and so on. Through the experimental results, we confirmed that the correlation results of software correlator are the same as Mitaka FX correlator and verified the effectiveness of it. In future, we expect that the developed software correlator will be the possible software correlator of KVN (Korean VLBI Network) with KJJVC by introducing the correlation post-processing and modifying the user interface as like GUI (Graphic User Interface).

• KAPE Magazine
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• s.250
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• pp.21-23
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• 2017

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.892-895
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• 2002

We propose new buffer management scheme for GFR service through FIFO queuing discipline. Proposed scheme can provide minimum bandwidth guarantees for GFR VCs as well as improve the fairness among the competing GFR VCs on a single FIFO queue. From simulation results, we demonstrate the proposed scheme fulfills the requirements of GFR service as well as improves the TCP throughput.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.69.2-69.2
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• 2012

한국천문연구원과 일본국립천문대는 2006년부터 한일공동으로 한일공동VLBI상관기(KJJVC)를 개발하였다. 한일상관센터(KJCC)에 각 구성시스템을 설치한 후 최근까지 시험운영을 수행하였으나 한일공동VLBI상관기의 핵심인 VLBI상관서브시스템(VCS)에서 프린지회전 모듈이 정상적으로 동작하지 않는 것을 발견하여, 일본국립천문대 및 제작사와 함께 이 문제를 해결하였다. 프린지 회전모듈의 문제점은 상관결과를 AIPS 등에서 분석하면, Fringe fitting후에 Cross-power spectrum의 진폭과 위상성분이 고주파 영역에서 감쇠하는 현상이다. 본 발표에서는 VCS 프린지 회전모듈의 문제점 해결과 KJJVC를 구성하는 각 구성시스템의 현황, 그리고 운영에 대해 간략히 기술한다.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.1095-1098
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• 1999

We have developed a speaker dependent voice command system(VCS) to control the sunroof in the car using RSC-164 VRP(Voice Recognition Processor). VCS consists of control circuits, microphone, speaker and user switch box. The control circuits include RSC-164, input audio preamplifier, memory devices, and relay circuit for sunroof control. It is designed robustly in various car noisy situations like audio volume, air conditioner, and incoming noise when window or sunroof opened. Each two users can control the car sunroof using seven voice commands on the Super TVS model and five voice commands on the Onyx model. It works well when we drive the car at over 100 km/h with the sunroof opened.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.1
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• pp.71-79
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• 2001

ATM networks with long-distance links, causing long propagation delays, may require virtual end system functions to provide ABR services. We survey several issues for implementing the control functions for ABR service in multiple VCs, required in the virtual ends, and propose a structure for implementation. In the proposed design, shared memory structure is used to control the cell emission of the multiple VCs for the ABR services in the virtual end systems.

• Asian Journal of Innovation and Policy
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• v.7 no.3
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• pp.534-563
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• 2018

Venture Capital Firms (VCs) encounter severe information asymmetry risks at almost every stage in their investment lifecycle. This paper explores the agency risks arising from information asymmetry during the stage of exits by VCs from the funded companies in their portfolio and how that impacts the incidence of specific types of type of exits (IPOs/M&As). In this empirical study, by using the data on IPO and M&A exits from venture capital-funded companies, we show how the ability of prospective buyers to better resolve agency risks is directly correlated with the incidence of the above exit types. Using the technique of logistic regression, we demonstrate that factors such as syndication, specialization focus of the VC firm (in terms of stage and sector) and the level of its social capital (proxied by its age and experience) drive the success rate of exits. This is one of first studies in context of exits from VC funded companies in the Indian context.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.871-880
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• 2011

The purpose of this research is to explore preservice earth science teachers' understanding of volcanic systems using a modified version of InVEST Volcanic Concept Survey (InVEST VCS, Parham et al., 2010). Results showed that participants' understanding of volcanic concepts was rather limited. Questions requiring only basic content knowledge (e.g., terminology associated with volcano) received high scoring responses, while questions requiring higher order thinking and deeper conceptual connections as the mechanics of volcanic eruption received low scoring responses. Specifically, the prediction of hazards and impacts on the environment appeared to be poorly understood. VCS results can be applied to improve the subject content knowledge as well as the pedagogical knowledge that instructors may use when they assess students' understanding of volcanism within a solid conceptual framework.