• 농촌계획
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• 제23권4호
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• pp.111-126
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• 2017

This study analyzes the impacts of agricultural water shortages in Korea using a combined top-down and bottom-up model. A multi-region multi-output agricultural sector model with detailed descriptions of production technologies and water and land resource constraints has been combined with a standard CGE model. The impacts of four different water shortage scenarios were simulated. It is shown that an active adaptation of crop choices occurs in even the regions with relatively abundant water resources in order to respond to the change in relative output prices caused by water shortages. We found that although the losses in production values are not quite large despite water shortages due to the price feedbacks, the loss in GDP is substantial. We show that our combined approach has advantages in deriving region and product specific production effects as well as the overall GDP loss effect of water shortages.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 추계학술대회 논문집
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• pp.489-490
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• 2008

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.153-153
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• 2022

Large-scale and accurate observations at fine spatial resolution through a means of remote sensing offer an effective tool for capturing rainfall variability over the traditional rain gauges and weather radars. Although satellite rainfall products (SRPs) derived using two major estimation approaches were evaluated worldwide, their practical applications suffered from limitations. In particular, the traditional top-down SRPs (e.g., IMERG), which are based on direct estimation of rain rate from microwave satellite observations, are mainly restricted with their coarse spatial resolution, while applications of the bottom-up approach, which allows backward estimation of rainfall from soil moisture signals, to novel high spatial resolution soil moisture satellite sensors over South Korea are not introduced. Thus, this study aims to evaluate the performances of a state-of-the-art bottom-up SRP (the self-calibrated SM2RAIN model) applied to the C-band SAR Sentinel-1, a statistically downscaled version of the conventional top-down IMERG SRP, and their integration for a targeted high spatial resolution of 0.01° (~ 1-km) over central South Korea, where the differences in climate zones (coastal region vs. mainland region) and vegetation covers (croplands vs. mixed forests) are highlighted. The results indicated that each single SRP can provide plus points in distinct climatic and vegetated conditions, while their drawbacks have existed. Superior performance was obtained by merging these individual SRPs, providing preliminary results on a complementary high spatial resolution SRP over central South Korea. This study results shed light on the further development of integration framework and a complementary high spatial resolution rainfall product from multi-satellite sensors as well as multi-observing systems (integrated gauge-radar-satellite) extending for entire South Korea, toward the demands for urban hydrology and microscale agriculture.

• 대한두개안면성형외과학회지
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• 제23권6호
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• pp.256-261
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• 2022

Background: Treating panfacial fractures (PFFs) can be extremely difficult even for experienced surgeons. Although several authors have attempted to systemize the surgical approach, performing surgery by applying a unidirectional sequence is much more difficult in practice. The purpose of this study was to review the literature on PFF surgery sequence and to understand how different surgical specialists-plastic reconstructive surgery (PRS) and oral maxillofacial surgery (OMS)-chose sequence and review PFFs fixation sequence in clinical cases. Methods: The PubMed and Google Scholar databases were scoured for publications published up until May 2020. Data extracted from the studies using standard templates included fracture part, fixation sequence, originating specialist, and the countries. Bibliographic details like author and year of publication were also extracted. Also, we reviewed the data for PFFs patients in the Trauma Registry System of Dankook University Hospital from 2011 to 2021. Results: In total, 240 articles were identified. This study comprised 22 studies after screening and full-text analysis. Sixteen studies (12 OMS specialists and 4 PRS specialists) used a "bottom-top" approach, whereas three studies (1 OMS specialist and 2 PRS specialists) used a "top-bottom" method. However, three studies (only OMS specialists) reported on both sequences. In our hospital, there were a total of 124 patients with PFF who were treated during 2011 to 2021; 64 (51.6%) were in upper-middle parts, 52 (41.9%) were in mid-lower parts, and eight (6.5%) were in three parts. Conclusion: Bottom-top sequencing was mainly used in OMS specialists, and top-bottom sequencing was used at a similar rate by two specialists in literature review. In our experience, however, it was hard to consistently implement unidirectional sequence suggested by a literature review. We realigned the reliable and stable buttresses first with tailoring individually for each patient, rather than proceeding in the unidirectional sequence like bottom-top or top-bottom.

• 전자공학회지
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• 제15권2호
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• pp.75-87
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• 1988

본 논문에서는 음성에 의한 man-machine communication의 핵심기술인 음성인식 및 합성의 전반적인 기술에 관하여 그 현황을 알아본다. 먼저 음성인식에서 해결되어야 할 문제점들을 고찰하고 격리단어 인식, 연결단어 인식, 그리고 연속언어 인식의 기술현황을 기술한다. 격리단어 인식에서는 pattern matching 방법에서 사용되는 입력어휘의 특징 추출, reference와의 유사도 측정, 유사도 측정 결과에 의한 인식결정에 관해서 논한다. 연결단어 및 연속언어 인식에서는 현재 연구가 되고 있는 "bottom-up approach"와 "top-down approach"에 관해서 설명하고 이들 방법의 어려운 점들을 고찰한다. 다음 음성 합성에서는 기존의 여러 가지 합성 방식을 검토하고 이들의 장단점을 기술한다. 마지막으로 한 예로서 한국어 text-to-speech 변환 시스템에 관하여 기술한다.

• 한국항행학회논문지
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• 제21권6호
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• pp.521-528
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• 2017

다수의 UAV가 다양한 임무를 수행하면서도 편대를 유지할 수 있도록 하는 집단적 지능을 갖춘 시스템을 구축하기 위해서는 AI에 관한 연구가 필수적이다. AI의 전형적인 접근 방법에는 전문가시스템을 비롯한 규칙기반의 논리 추론방식인 '하향식' 접근 방법과 인공신경회로망, Flocking Algorithm과 같이 단순 개체간의 부분적 상호작용을 통해 전체적인 행동이 결정되는 '상향식' 접근 방법이 있다. 기존의 Flocking Algorithm과 같은 연구에서는 개개인은 개별적인 임무를 수행 할 수 없다. 또한 UAV의 편대비행과 같은 연구에서는 편대의 부분적인 결함으로 발생하는 문제에 대해 유연하게 대처 할 수 없다. 본 논문에서는 다중에이전트 시스템을 통해 하향식 접근 방법과 상향식 접근 방법 간의 유기적 통합을 제시하고, 이를 통해, 유연한 임무수행이 가능한 편대 비행 알고리즘을 제시하였으며, 시뮬레이션을 통해 대형형성 및 충돌회피 등 유효성을 확인하였다.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.15-19
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• 2001

Creating an artificial strain with a minimal gene set for a specific purpose is every biologist's dream. With the complete genome sequencing of more than 50 microorganisms and extensive functional analyses of their genes, it is possible to design a genetic blueprint for a simple custom-designed microbe with the minimal gene set. Two different approaches are being considered. The first 'top-down' approach is trimming the genome to a minimal gene set by selectively removing genes of an organism thought to be unnecessary based on microbial genomics. The second 'bottom-up' approach is to synthesize the proposed minimal genome from basic chemical building blocks. The 'top-down' approach starting with the genome of a well known microorganism is more technically feasible, whereas the bottom-up approach may not be attainable in the nearest future because of the lack of the complete functional analysis of the genes needed for a life. Here in this study, we used the top-down approach to minimize the E. coli genome to create an artificial organism with 'core' elements for self-sustaining and self-replicating cells by eliminating unnecessary genes. Using several different kinds of sophisticated deletion techniques combined with a p:1age and transposons, we deleted about 19％ of the E. coli genome without causing any damages to cellular growth. This smaller E. coli genome will be further reduced to a genome with a minimal gene l;et essential for cell life. This minimized E. coli genome can lead to the construction of many custom-designed strains with myriad practical and commercial applications.

• 한국주거학회논문집
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• 제17권3호
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• pp.51-60
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• 2006

Ten years have passed since the Demolishing Walls Campaign has started in Daegu. Recently, the campaign influenced to the other cities in Korea, such as Seoul, Incheon and Busan with various names regarding cities' circumstances. In these context, the study aims to highlight the identity of the Demolishing Walls Campaign compare Daegu with other cities where similar movement has started. In addition, the study evaluates the campaign in terms of physical, psychological and economical aspects to suggest some practical suggestion for the development of the campaign based on questionnaire survey. The research findings are as follows. The research shows that the identity of the Daegu Campaign is started by bottom-up approach based on citizens' participation compare with others cities' campaigns which are mainly started by the local government so called top-down method. The Daegu campaign influences the local people aware of their potential abilities in positively improving urban environment. The results of survey also highlights the advantages of green spaces which by the campaign in terms of environmental and economical aspects. Newly generating urban greens accept and store heat which Influences urban microclimate conditions and it possibly affects energy savings of the city. Most of survey participants eager to continue this campaign which shows positive results in various aspects by the local people. Therefore, the city government building a coalition of local people, NGOs, and interest group to keep the identity of the campaign in Daegu.

• Journal of Advanced Marine Engineering and Technology
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• 제36권5호
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• pp.674-682
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• 2012

A new intelligent stereo vision sensor system was studied for the motion and depth control of unmanned vehicles. A new bottom-up saliency map model for the human-like active stereo vision system based on biological visual process was developed to select a target object. If the left and right cameras successfully find the same target object, the implemented active vision system with two cameras focuses on a landmark and can detect the depth and the direction information. By using this information, the unmanned vehicle can approach to the target autonomously. A number of tests for the proposed bottom-up saliency map were performed, and their results were presented.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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• pp.331-336
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• 2005

Post translational modifications (PTMs) discovery is an important problem in proteomic. In the past, people discover PTMs by Tandem Mass Spectrometer based on ‘bottom-up’ strategy. However, such strategy suffers from the problem of failing to discover all PTMs. Recently, due to the improvement in proteomic technology, Taylor et al. proposed a database software to discover PTMs with ‘topdown’ strategy by FTMS, which avoids the disadvantages of ‘bottom-up’ approach. However, their proposed algorithm runs in exponential time, requires a database of proteins, and needs prior knowledge about PTM sites. In this paper, a new algorithm is proposed which can work without a protein database and can identify modifications in polynomial time. Besides, no prior knowledge about PTM sites is needed.