The Entropy of Recursively-Indexed Geometric Distribution

Sangsin Na,Young Kil Kim,Haing Sei Lee 한국정보과학회 1996 Journal of Electrical Engineering and Information Vol.1 No.1

This paper proves by straightforward computation an interesting property of a recursive indexing: it preserves the entropy of a geometrically-distributed stationary memoryless source. This result is a pleasant surprise because the recursive indexing, though one-la-one, is a symbol-ta-string mapping and the entropy is measured in terms of the source symbols. This preservation of the entropy implies that the minimum average number of bits needed to represent a geometric memoryless source by the recursive indexing followed by a good binary encoder of a finite input alphabet remains the same as that by a good encoder of an infinite input alphabet. Therefore, the recursive indexing theoretically keeps coding optimality intact. For this reason recursive indexing can provide an interface for a binary code with a finite code book that performs reasonably well for a source with an infinite alphabet.

Attitude and Position Control using Dynamic Modeling of Quadrotor Flight

Sangsin Jeon,Taeseok Jin 한국정보통신학회 2019 2016 INTERNATIONAL CONFERENCE Vol.11 No.1

Climate Change Adaptive Implementation Assessment Proposal for Local Governments Utilizing Vulnerability Index

Sangsin Lee 강원대학교 산림과학연구소 2019 Journal of Forest Science Vol.35 No.1

This study applies the concept of climate change vulnerability assessment in order to suggest climate change adaptation effects in a quantitative manner, given that previous studies have hitherto rely on qualitative assessment, as climate change adaptive policies are currently being implemented by local governments of Korea. The vulnerability assessment tool used in this study is VESTAP (“Vulnerability assESsment Tool to build a climate change Adaptation Plan”), which was developed by the Korea Adaptation Center for Climate Change (KACCC), and applied to gauge the vulnerability of pine trees to diseases and pests within Chungcheongnam-do. The climate change adaptation project for vulnerability improvement was assessed only in terms of forest disaster prevention and change in regional climate change vulnerabilities within 16 regions of Chungcheongnam-do as the result of 2016 Climate Change Adaptation Project (Forest Disaster Prevention Project). As a result, it was observed that climate change adaptive capacity has improved according to change in the area of forestland with disaster prevention, and the vulnerability indicator decreased, confirming the impact of the climate change adaptation (forest disaster prevention) project. Also, analysis of regional climate change adaptation project scales and change in vulnerabilities allowed us to determine the regional propriety of climate change adaptation (forest disaster prevention) projects launched in 2016.

The Entropy of Recursively-Indexed Geometric Distribution

Sangsin Na,Young Kil Kim,Haing Sei Lee 대한전기학회 1996 Journal of Electical Engineering and information S Vol.1 No.1

The Impact of Government Innovation Subsidies on the Survival of SMEs in Korea

Sangsin Kim 과학기술정책연구원 2018 STI Policy Review Vol.9 No.1

This study analyzed the effect of the government R&D subsidy program on long-term firm survival. In order to estimate the average treatment effect for the treated group, we used the survival analysis and matching method by constituting a comprehensive dataset of more than 90,000 observations. The analysis results show that the government R&D subsidy has a negative impact on long-term firm survival. In particular, not only the subsidy does not have a statistically significant effect on firm survival in the relatively short-term, the survival probability of the subsidized firms is statistically significantly lower than the non-subsidized firms after six years. These results can be seen as weakening the justification of government R&D support. There may be problems in the subsidy policy itself and the process of selection of subsidy awardees; however, the more fundamental problem is that the subsidy policy is concluded as the one-time event. Admittedly, it would be difficult for the government to precisely manage the subsidized projects over a long term period. However, in the case of a project in which short-term performance is detected, it would be necessary to provide a step-by-step support to strengthen the firm’s competitiveness through further support and continuous development of performance. Of course, mid- and long-term evaluations of subsidy support policy should be performed in parallel with such phased support.

The Appearance of a Candidate Site for a Primary Melanoma: A 5 Year-gap with a Melanoma of an Unknown Site

Sangsin Lee,이효진,오상하,임명,Jeung-Hoon Lee,서영준,Young Lee 대한피부과학회 2011 Annals of Dermatology Vol.23 No.-

Although more than 90% of melanomas have cutaneous origins, melanomas sometimes present metastatically with no apparent primary lesion. A 62-year-old female presented with black pigmentation on her left thumbnail that had begun 2 years earlier and after the biopsy, she was diagnosed with malignant melanoma. Interestingly, 7 years earlier, a 4cm palpable mass on her left axilla had been diagnosed as melanoma from an unknown primary site (MUP) with the involvement of an axillary lymph node. We speculate that the melanoma of the left thumb was the primary site and the melanoma in the axilla was a metastasis from the left thumb,and suggest several hypotheses explaining the appearance of the primary lesion as acral lentiginous melanoma after detecting a metastatic site. We consider this case interesting because it helps us to understand the pathogenesis of MUP and reminds physicians to conduct careful periodical work-ups of melanoma patients, and highlights the importance of continued long-term follow-up, especially for patients with MUP. (Ann Dermatol 23(S2) S274∼S278, 2011)

Two-Dimensional Probability Functions of Morphological Dilation and Erosion of a Memoryless Source

Sangsin Na,Tae Young Choi 한국정보과학회 1996 Journal of Electrical Engineering and Information Vol.1 No.1

This paper derives the two-dimensional probability distribution and density functions of morphological dilation and erosion of a one-dimensional memoryless source and reports numerical results for a uniform source, thus providing methodology for joint distributions for other morphological operations. The joint density functions expressed in closed forms contain the Dirac delta functions due to the joint discontinuity within the dilation and erosion. They also exhibit symmetry between these two morphological operations. Applications of the result can be found in the computation of the autocorrelation and the power spectral density functions of dilated and/or eroded sources, in the computation of other higher moments thereof, and in multidimensional quantization.

Two-Dimensional Probability Functions of Morphological Dilation and Erosion of a Memoryless Source

Sangsin Na,Tae Young Choi 대한전기학회 1996 Journal of Electical Engineering and information S Vol.1 No.1

기후변화 대응을 위한 발전소 온배수 활용 양식업 경제성 분석

이상신(Sangsin Lee),김상문(ShangMoon Kim),엄기증(GiJeung Um) 한국방재안전학회 2011 한국방재안전학회 논문집 Vol.4 No.2

In order to resolve the problem of change in global climate which is worsening as days go by and to preemptively cope with strengthened restriction on carbon emission, the government enacted ‘Framework Act on Low Carbon Green Growth’ in 2010 and selected green technology and green industry as new national growth engines. For this reason, the necessity to use the un-utilized waste heat across the whole industrial system has become an issue, and studies on and applications of recycling in the agricultural and fishery fields such as cultivation of tropical crops and flatfishes by utilizing the waste heat and thermal effluent generated by large industrial complexes including power plants are being actively carried out. In this study, we looked into the domestic and overseas examples of having utilized waste heat abandoned in the form of power plant thermal effluent, and carried out economic efficiency evaluation of sturgeon aquaculture utilizing thermal effluent of Yeongwol LNG Combined Cycle Power Plant in Gangwon-do. In this analysis, we analyzed the economic efficiency of a model business plan divided into three steps, starting from a small scale in order to minimize the investment risk and financial burden, which is then gradually expanded. The business operation period was assumed to be 10 years (2012~2021), and the NVP (Net Present Value) and economic efficiency (B/C) for the operation period (10 years) were estimated for different loan size by dividing the size of external loan by stage into 80% and 40% based on the basic statistics secured through a site survey. Through the result of analysis, we can see that reducing the size of the external loan is an important factor in securing greater economic efficiency as, while the B/C is 1.79 in the case the external loan is 80% of the total investment, it is presumed to be improved to 1.81 when the loan is 40%. As the findings of this study showed that the economic efficiency of sturgeon aquaculture utilizing thermal effluent of power plant can be secured, it is presumed that regional development project items with high added value can be derived though this, and, in addition, this study will greatly contribute to reinforcement of the capability of local governments to cope with climate change. 갈수록 심해지고 있는 전 세계적인 기후변화 문제를 해결하고 탄소배출 규제 강화에 선제적으로 대응하기 위해 정부는 2010년 ‘저탄소 녹색성장 기본법’을 제정하고 녹색기술과 녹색산업을 국가 신성장 동력으로 삼고 있다. 이에따라 산업시스템 전반에 걸쳐 미활용되는 폐열 사용에 대한 필요성이 부각되고 있으며, 발전소를 비롯한 대규모 산업단지에서 발생하는 폐열 및 온배수를 활용하여 열대작물재배, 넙치 등 농어업분야 재활용에 대한 연구와 적용이 활발히 진행되고 있다. 본 연 구에서는 발전소 온배수 형태로 버려지는 폐열을 활용한 국내외 활용사례를 살펴보고 강원도 영월 LNG복합발전소의 온배수를 활용한 철갑상어 양식에 대한 경제성 평가를 실시하였다. 경제성 분석에서는 투자 리스크와 재정부담을 최소화하기 위 해서 규모를 작게 시작해서 점진적으로 확대하는 3단계에 걸친 시범사업계획의 경제성을 분석하였다. 사업운영기간은 10년 (2012~2021)으로 가정하고 현지조사로 확보한 기초통계량에 근거하여 단계별 외부 차입금 규모를 80%와 40%로 구분함으로써, 차입금 규모에 따른 운영 기간 내(10년) NPV(순 현재가) 및 경제성(B/C)을 추정하였다. 분석결과 외부차입금이 총 투자금액의 80%를 차지하는 경우에는 B/C가 1.79인데 반해 차입규모가 40%인 경우에는 1.81로 향상되는 것으로 추정되어 외 부차입금 규모를 축소하는 것이 보다 큰 경제성을 확보하는데 중요한 요인이 됨을 알 수 있다. 본 연구결과로 발전소 폐열을 활용한 철갑상어 양식의 경제성 확보가 가능한 것으로 나타남에 따라 이를 통한 고부가가치 지역발전 사업 아이템 도출 이 가능할 것이며, 더불어 지자체의 기후변화대응 역량강화에도 크게 기여할 것으로 사료된다.

불일치된 최적 라플라스 양자기의 신호대잡음비 점근식의 유도

나상신(Sangsin Na) 한국통신학회 2008 韓國通信學會論文誌 Vol.33 No.5C

이 논문은 최소 평균제곱오차 라플라스 양자기가 평균이나 표준편차가 불일치된 신호에 적용될 때 야기되는 평균제곱오차 왜곡과 신호대 양자화 잡음비의 점근식을 유도한다. 이들 식은 양자점의 개수 Ν, 평균값의 변이량 μ, 양자기 설계 기준으로 사용된 표준편차에 대해 적용되는 신호의 표준편차 비율 로써 왜곡과 신호대잡음비의 직접적인 관계를 명확히 표시하고 있다. 수치 결과에 의하면, 논문의 주 근사식은, 요율 R=?₂Ν이 6 이상인 경우에, 상당히 넓은 μ와 ρ에 대해 신호대잡음비 참값의 1% 이내의 값을 예측하여 정확도가 아주 높은 것으로 판단된다. 이 논문을 통해 새로 발견된 점은 첫째 ρ>3/2인 분산 강불일치의 경우에 신호대잡음비는 g/p ㏈/bit 비율로 증가한다는 것과 둘째 최적 균일양자기는, 비록 최적으로 설계되었지만, 분산 임계불일치보다 조금 더 불일치된 것임을 밝힌 점이다. 또 μ에 의한 신호대잡음비 손실은 비교적 크지 않은 것이 관찰되었다. 여기에 유도된 공식들은, 단구간 분산이 변하는 라플라스 분포로 잘 모형되는 음성이나 음악 신호를 하나의 양자기로 양자화하는 경우에 쓰임새가 있을 것으로 사료된다. The paper derives asymptotic formulas for the MSE distortion and the signal-to-noise ratio of a mismatched fixed-rate minimum MSE Laplacian quantizer. These closed-form formulas are expressed in terms of the number Ν of quantization points, the mean displacement μ, and the ratio ρ of the standard deviation of the source to that for which the quantizer is optimally designed. Numerical results show that the principal formula is accurate in that, for rate R=?₂Ν≥6, it predicts signal-to-noise ratios within 1% of the true values for a wide range of μ and ρ. The new findings herein include the fact that, for heavy variance mismatch of ρ>3/2, the signal-to-noise ratio increases at the rate of g/p ㏈/bit, which is slower than the usual 6 ㏈/bit, and the fact that an optimal uniform quantizer, though optimally designed, is slightly more than critically mismatched to the source. It is also found that signal-to-noise ratio loss due to μ is moderate. The derived formulas can be useful in quantization of speech or music signals, which are modeled well as Laplacian sources and have changing short-term variances.