• Journal of Semiconductor Engineering
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• 제2권3호
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• pp.136-141
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• 2021

This paper analyzes the tree expansion for multiple-input multiple-output (MIMO) detection in the viewpoint of hardware implementation. The tree expansion is to calculate path metrics of child nodes performed in every visit to a node while traversing the detection tree. Accordingly, the tree-expansion unit (TEU), which is responsible for such a task, has been an essential component in a MIMO detector. Despite the paramount importance, the analyses on the TEUs in the literature are not thorough enough. Accordingly, we further investigate the hardware complexity of the TEUs to suggest a guideline for selection. In this paper, we focus on a pair of major ways to implement the TEU: 1) a full parallel realization; 2) a transformation of the formulae followed by common subexpression elimination (CSE). For a logical comparison, the numbers of multipliers and adders are first enumerated. To evaluate them in a more practical manner, the TEUs are implemented in a 65-nm CMOS process, and their propagation delays, gate counts, and power consumptions were measured explicitly. Considering the target specification of a MIMO system and the implementation results comprehensively, one can choose which architecture to adopt in realizing a detector.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2238-2249
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• 2020

In a seismic PSA, dependency among seismic failures of components has not been explicitly modeled in the fault tree or event tree. This dependency is separately identified and assigned with numbers that range from zero to unity that reflect the level of the mutual correlation among seismic failures. Because of complexity and difficulty in calculating combination probabilities of correlated seismic failures in complex seismic event tree and fault tree, there has been a great need of development to explicitly model seismic correlation in terms of seismic common cause failures (CCFs). If seismic correlations are converted into seismic CCFs, it is possible to calculate an accurate value of a top event probability or frequency of a complex seismic fault tree by using the same procedure as for internal, fire, and flooding PSA. This study first proposes a methodology to explicitly model seismic dependency by converting correlated seismic failures into seismic CCFs. As a result, this methodology will allow systems analysts to quantify seismic risk as what they have done with the CCF method in internal, fire, and flooding PSA.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.270-274
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• 2006

This paper proposes a Chaos Pulse Width Modulation(CPWM) technique. For generating the chaotic numbers by chaos phenomenon, chaos area $\lambda$=0.99 in bifurcation tree of the proposed double tent mapping is used. A micro-controller is used for the generation of chaos numbers and triangular carrier with chaotic frequency is obtained through the process of frequency modulation according to the generated chaos numbers. The experiments are executed with the 1.5kw induction motor coupled with a 2.5A load. The experimental results show that the voltage / current spectra are spread to a chaotic range, and the switching noise of motor is reduced by the proposed method compared to the fixed frequency PWM method.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.309-312
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• 2005

The need for LBS (Loc,ation Based Services) is increasing due to the wnespread of mobile computing devices and positioning technologies~ In LBS, there are many applications that need to manage moving objects (e.g. taxies, persons). The moving object join operation is to make pairs with spatio-temporal attribute for two sets in the moving object database system. It is import and complicated operation. And processing time increases by geometric progression with numbers of moving objects. Therefore efficient methods of spatio-temporal join is essential to moving object database system. In this paper, we apply spatial join methods to moving objects join. We propose two kind of join methods with TB- Tree that preserves trajectories of moving objects. One is depth first traversal spatio-temporaljoin and another is breadth-first traversal spatio-temporal join. We show results of performance test with sample data sets which are created by moving object ,generator tool.

• Journal of Ecology and Environment
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• 제35권2호
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• pp.91-98
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• 2012

This study was performed in order to suggest the possibility of tree species classification using high-resolution QuickBird-2 images spectral characteristics comparison(digital numbers [DNs]) of tree species, tree species classification, and accuracy verification. In October 2010, the tree species of three conifers and eight broad-leaved trees were examined in the areas studied. The spectral characteristics of each species were observed, and the study area was classified by image classification. The results were as follows: Panchromatic and multi-spectral band 4 was found to be useful for tree species classification. DNs values of conifers were lower than broad-leaved trees. Vegetation indices such as normalized difference vegetation index (NDVI), soil brightness index (SBI), green vegetation index (GVI) and Biband showed similar patterns to band 4 and panchromatic (PAN); Tukey's multiple comparison test was significant among tree species. However, tree species within the same genus, such as $Pinus$ $densiflora-P.$ $rigida$ and $Quercus$ $mongolica-Q.$ $serrata$, showed similar DNs patterns and, therefore, supervised classification results were difficult to distinguish within the same genus; Random selection of validation pixels showed an overall classification accuracy of 74.1% and Kappa coefficient was 70.6%. The classification accuracy of $Pterocarya$ $stenoptera$, 89.5%, was found to be the highest. The classification accuracy of broad-leaved trees was lower than expected, ranging from 47.9% to 88.9%. $P.$ $densiflora-P.$ $rigida$ and $Q.$ $mongolica-Q.$ $serrata$ were classified as the same species because they did not show significant differences in terms of spectral patterns.

• 환경생물
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• 제21권2호
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• pp.120-125
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• 2003

본 연구는 토지피복현황과 수림의 계층구조 등이 다양한 도시녹지를 대상으로 기온 및 급도에 미치는 영향물 점성 빛 정량적으로 파악하기 위해 녹지내의 기온 및 습도를 관측하였다. 그 데이터클 바탕으로 녹지내의 토지피복현황과 기온 및 습도분포, 녹지내의 수목그루와 녹적량및 습도와의 관련성을 회귀분석 둥에 의해 해석 하였다. 그 결과, 고온역은 인공구조물과 나지 주변에서, 저온역은 수림지와 수면 주변에서 형성되었다. 습도는 기온분포에 거의 대응하는 형태로 고온역이 저습역이고, 저온역이 고습역으로 나타났다. 또한, 수림의 계층구조가 2,3층으로 덮여 있는 구역과 수면을 핵으로 그 주변은 수림으로 둘러싸인 구역이 상대적으로 높은 습도를 나타냈다. 수루그루 빛 녹적량의 증가는 어떤 수고라도 습도의 상승에 효과적이고 그 효율은 교목, 소교목, 관루의 순이다.

• 한국산학기술학회논문지
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• 제17권12호
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• pp.226-231
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• 2016

본 논문에서는 배리어 옵션의 가격 산정을 위해 이항분포모형을 사용한다. 경로의존형 옵션인 배리어 옵션의 가격산정을 위해서는 이항트리의 말단에서 역방향으로 진행하면서 개별 노드들의 옵션 가치를 계산하여 옵션 가격을 산정하게 된다. 이항트리의 말단에서는 배리어 도달 여부를 판단하기 어려운데, 카탈란 수를 일반화하여 배리어에 도달하지 않은 경우의 수를 구하고자 한다. 일정한 범위에서 움직이는 경로의 수를 파악하기 위해 카탈란 수에 상한과 하한을 부여하는 방식으로 일반화한다. 이항분포모형에서 배리어 도달 여부는 가격 상승과 가격 하락 횟수의 차이가 일정한 범위에 있는지를 판단하여 결정한다. 상한과 하한을 부여한 일반화된 카탈란 수를 활용하여 가격 상승과 가격 하락 횟수의 차이가 일정한 범위에 있는 경우의 수를 구할 수 있으면, 이항트리 말단에서 배리어에 도달하지 않았을 확률을 계산할 수 있다. 이항트리 말단에서의 옵션 가치와 배리어에 도달하지 않았을 확률을 이용하여 만기의 옵션 기대값을 계산하고 이를 현재 시점으로 할인하여 배리어 옵션 가격을 구하게 된다. 이항분포모형을 이용한 기존의 방법은 중간 단계의 옵션 가치를 모두 계산해야 하지만, 일반화된 카탈란 수를 적용한 방법은 이항트리 말단에서의 옵션 가치만으로도 옵션 가격 산정이 가능하고 만기시점의 옵션행사 확률에 대한 분포를 얻을 수 있다. 상한과 하한을 부여하여 일반화된 카탈란 수는 배리어 옵션 가격 산정뿐만 아니라 다양한 분야에 활용할 수 있을 것으로 기대된다.

• 대한한의학원전학회지
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• 제30권4호
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• pp.49-67
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• 2017

Objective : Heavenly stems and Earthly branches is a tool used for understanding the virtue of Yin Yang and Five elements. Korean medicine understands the changes in Wuyun through the Ten Heavenly stems, and understand the changes of Liuqi through the Twelve Earthly branches. An accurate understanding of the definitions of Heavenly Stems and Earthly branches and the concept of each of the 10 stems is of vital importance. Method : The paper first reviews the origin, history, and significance of the Heavenly stems and Earthly branches before studying the definitions of the stems and branches as laid out in the works of Yu Onseo, Lee Samun, and Han Dongseok. The paper then reviewed the concept of the each of the ten stems through researching the texts of Seoulmunhaeja, the annotations of the four great Seolmuns, and the texts of Jeongyeokwonui. Result & Conclusion : Heavenly stems and Earthly branches have been in use since more than 6,000 years ago. The central numbers in the changes of Heaven and Earth are five and six. Each number functions with duality, yin and yang, meaning there are ten Heavenly numbers ($5{\times}2=10$) and 12 Earthly numbers ($6{\times}2=12$) which oversees all of the cosmic changes. Stems become the body and signifies water. Branches become the use and signifies divided fire. The meanings of the letters Gab Eul Byeong Jeong Mu Gi Gyeong Sin Im Gye originate from the one year life of a tree which grows, bears fruits, processes Yang qi, and awaits for the next spring. The reason a tree is used is because there is nothing better in studying in detail the changes of a living being through a year.

• Food Science and Biotechnology
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• 제15권5호
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• pp.752-755
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• 2006

This study was carried out to investigate the effects of ash tree leaf extract (ALE) on acetaminophen (APAP)-induced hepatotoxicity in mice. Hepatoprotective effects were detected by biochemical analysis of hepatic enzymes and histopathological examination of the liver. BALB/c mice were divided into three groups: 'normal' control mice, APAP-treated control mice, and mice pretreated with ALE and treated with APAP. A single dose of APAP markedly increased levels of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Light micrographs of liver cells stained with hematoxylin and eosin showed that APAP induced severe centrilobular necrosis, degeneration, and infiltration by inflammatory cells. Moreover, APAP caused the numbers of TUNEL-positive hepatocytes to increase and caused glycogen content to decrease as observed by Periodic acid-Schiff stain. However, pretreatment with ALE for 7 days prior to the administration of APAP significantly decreased plasma levels of AST and ALT. Histological findings demonstrated that ALE pretreatment alleviated APAP-induced liver damage, and induced the regeneration of liver tissue and restoration of glycogen. These results indicate that ash tree leaf extract exerts a protective effect against APAP-hepatotoxicity induced injury.

• 한국안전학회지
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• 제24권4호
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• pp.1-10
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• 2009

The characteristics of smoke emissions from diesel heavy duty vehicles which weigh over 5.5 tons was investigated by driving the vehicles with both the Lugdown 3 modes in the chassis dynamometer and tree accelerating mode under no load. The vehicles include commercial vehicles such as bus, microbus, trucks and specialized vehicles, etc. The total numbers of the vehicles tested were 200. The light extinction method was used to measure the smoke emissions from the vehicles tail pipe. The values of the smoke emissions in the tree accelerating mode showed $0{\sim}20%$ band nearly independent of both the mileage and year of production of the tested vehicles, while those in the Lugdown 3 modes showed $0{\sim}99%$ of wide band. The correlation coefficients between the values of the smoke emissions with both the Lugdown 3 modes and the free acceleration mode were 0.12, 0.08, 0.12, respectively. The inspection with Lugdown 3 modes is better one than that with tree acceleration from the point of exact inspection of the diesel vehicles' smoke emission.