• 디지털융복합연구
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• 제12권12호
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• pp.329-335
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• 2014

본 논문에서는, PB/MC-CDMA 시스템의 성능을 향상시키기 위한 방법으로 파일롯 심볼 및 데이터 심볼을 이용한 결정 귀환 채널 추정 기법에 대하여 연구하였다. PB/MC-CDMA 시스템은 주파수 선택적 페이딩 채널 환경에서 주파수 다이버시티 이득 및 주파수 영역 등화기를 통하여 좋은 비트오율을 얻을 수 있다. 그러나 정확한 채널 추정이 되지 않을 경우 사용자간의 심각한 간섭이 발생하기 때문에 성능 저하가 일어난다. 제안 시스템은 1차 채널 추정 값과 2차 채널 추정된 값을 결정 귀환시켜 채널을 추정함으로써 다중사용자 환경에서 시스템의 성능을 향상 시킨다. 제안시스템의 성능 평가는 컴퓨터 시뮬레이션을 통하여 수행하였다. 본 논문에서 제안시스템을 통해 사용자간의 간섭으로 인한 성능 저하를 보상하여 비트오율이 향상될 뿐만 아니라 채널 추정을 위한 파일롯 심볼의 수를 줄일 수 있어 기존의 시스템보다 더 우수한 성능을 가지는 것을 확인 하였다.

• 한국물환경학회지
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• 제31권2호
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• pp.120-133
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• 2015

Due to increasing impervious surfaces resulting from urbanization and industrialization which are directly linked to urban inundation and non-point pollutants runoff, there is a need to manage them systematically. A management over urban impervious surfaces calls for pervious/impervious maps, which enable viewing the distribution of impervious surfaces. Nevertheless, relevant data are absent as now. In this respect, despite the diversity of proposed methods, pilot implementation and accuracy verification have never been conducted. Therefore, this study is aimed to produce a pilot pervious/impervious map based on previously proposed methods and to elucidate its pros and cons with a view to proposing a method for producing a GIS-based optimal pervious/impervious map. Following previously proposed methods, a pervious/impervious map of Bupyeong-gu, Incheon was produced. Then, a method of producing optimal pervious/impervious maps applicable to urban areas was proposed through the comparison of pros and cons of relevant spatial data. As a result, the map had been confirmed 99.2% of classification accuracy. Based on the present findings, future studies should establish a standardized method for producing. Also, this method should be used to produce pervious/impervious maps of other regions so that it can be applied to managing impervious surfaces in major urban areas nationwide.

• ALGAE
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• 제25권3호
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• pp.141-153
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• 2010

Seagrass epiphyte blooms potentially have important economic and ecological consequences in Tampa Bay, one of the Gulf of Mexico's largest estuaries. As part of a Tampa Bay pilot study to monitor the impact of environmental stresses, precise characterization of epiphyte diversity is required for efficient management of affected resources. Thus, epiphyte diversity may be used as a rational basis for assessment of ecosystem health. In May 2001, epiphytic species encompassing green, brown and red macroalgae were manually collected from dense and sparse seagrass beds of Thalassia testudinum and Syringodium filiforme. A total of 20 macroalgal epiphytes, 2 Chlorophyta, 2 Phaeophyta, and 16 Rhodophyta, were found on T. testudinum and S. filiforme seagrass at the four sampling sites (Bishop Harbor, Cockroach Bay, Feather Sound, and Mariposa Key). The Rhodophyta, represented by 16 species, dominated the numbers of species. Among them, the thin-crusted Hydrolithon farinosum was the most commonly found epiphyte on seagrass leaves. Species number, as well as species frequency of epiphytes, is higher at dense seagrass sites than sparse seagrass sites. Four attachment patterns of epiphytes can be classified according to cortex and rhizoid development: 1) creeping, 2) erect, 3) creeping & erect, and 4) erect & holding. The creeping type is characterized by an encrusting thallus without a rhizoid or holdfast base. Characteristics of the erect type include a filamentous thallus with or without a cortex, and a rhizoid or holdfast base. The creeping and erect type is characterized by a filamentous thallus with a cortex and rhizoid. A filamentous thallus with a cortex, holdfast base, and host holding branch is characteristics of the erect and holdfast attachment type. This study characterized each species found on the seagrass for epiphyte identification.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제26권2호
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• pp.99-115
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• 2023

Purpose: Exclusive breastfeeding promotes gut microbial compositions associated with lower rates of metabolic and autoimmune diseases. Its cessation is implicated in increased microbiome-metabolome discordance, suggesting a vulnerability to dietary changes. Formula supplementation is common within our low-income, ethnic-minority community. We studied exclusively breastfed (EBF) neonates' early microbiome-metabolome coupling in efforts to build foundational knowledge needed to target this inequality. Methods: Maternal surveys and stool samples from seven EBF neonates at first transitional stool (0-24 hours), discharge (30-48 hours), and at first appointment (days 3-5) were collected. Survey included demographics, feeding method, medications, medical history and tobacco and alcohol use. Stool samples were processed for 16S rRNA gene sequencing and lipid analysis by gas chromatography-mass spectrometry. Alpha and beta diversity analyses and Procrustes randomization for associations were carried out. Results: Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria were the most abundant taxa. Variation in microbiome composition was greater between individuals than within (p=0.001). Palmitic, oleic, stearic, and linoleic acids were the most abundant lipids. Variation in lipid composition was greater between individuals than within (p=0.040). Multivariate composition of the metabolome, but not microbiome, correlated with time (p=0.030). Total lipids, saturated lipids, and unsaturated lipids concentrations increased over time (p=0.012, p=0.008, p=0.023). Alpha diversity did not correlate with time (p=0.403). Microbiome composition was not associated with each samples' metabolome (p=0.450). Conclusion: Neonate gut microbiomes were unique to each neonate; respective metabolome profiles demonstrated generalizable temporal developments. The overall variability suggests potential interplay between influences including maternal breastmilk composition, amount consumed and living environment.

• 한국환경복원기술학회지
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• 제13권3호
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• pp.1-12
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• 2010

As social environment of Korea was changing, the cremation is increased instead of traditional funeral culture. Therefore woodland burial appears new funeral culture in Korea. This research had been executed to find out the problem of soil and vegetation environments of woodland burial forest. The case study was worked at woodland burial in Incheon Family funeral services which was national pilot project. The problem of soil and vegetation environments were surveyed in slope, soil compaction, actual vegetation, vegetation communities, structure of forest communities and so on. The results from this study indicate that woodland burial construction didn't consider the damage and management of vegetation environment in Incheon Family funeral Services. Problems for the Law on funeral facilities of Korea is a lack of natural friendly standards for slope, management on structure of forest communities, facilities for users in it. It had steep topography, soil compaction, reduction of species diversity and poor plant growth on woodland burial in Incheon Family funeral Services. Therefore the users of it increase in the future, vegetation environment of woodland burial will be devastated. And so we need to improve standards of woodland burial construction and management to settle down burial culture of woodland burial in Korea.

• 농업과학연구
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• 제38권2호
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• pp.315-324
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• 2011

Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, stream bank stabilization methods, and stream flow processes are described and interpreted for selected nature-friendly small stream bank protection of Goesan, central Korea. Idong Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods which was nature-friendly stream bank protection. The project aim to maintain or increase stream bank stabilization ecosystem goods and services while protecting downstream and stream bank ecosystem. A number of protecting methods which were a Flight of fieldstone, Vegetation block, Green river block, Stone net, Green environment block, Eco friendly cobble, Vegetation mat and Geo-green cell and Firefly block were applied on the bank of Idong stream. The stream sites have been monitored about vegetation conditions each method in 2007. We selected six points to separately investigate in left and right bank. The main purpose of this study was to find out suitable methods and to improve stream restoration techniques for ecosystem. On the stream bank, H environment block method (9.7) was the highest average of vegetation coverage and Firefly block method (3.87) was the lowest average in applied methods.

• 대한전자공학회논문지TC
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• 제41권11호
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• pp.81-86
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• 2004

부호분할다중접속(CDMA: Code Division Multiple Access) 시스템의 역방향링크에서 수신 빔 성형 기법을 사용할 경우, 빔 성형 이득을 얻는 반면 전력 제어에 의해 불충분한 파일롯 전력으로 인해 채널 추정이 부정확해진다. 이 논문에서는 상관된 단일-입력 다중-출력(SIMO: Single-Input Multiple-Output) 채널에서 불충분한 파일롯 전력으로 인한 문제를 해결하기 위한 수신 빔 성형 방식을 제안하고자 한다. 제안된 복합형 빔 성형 방식(hybrid beamformer)은 수신 안테나들을 그룹 지어서, 각 그룹 당 수신 빔 방향(DOA: Direction-of-Arrival) 기반의 빔 성형 후에, 그룹별 출력을 최대 비 결합(MRC: Maxim Ratio Combining)하는 방식으로, 공간적으로 상관된 SIMO 채널의 디버시티 이득을 얻으면서 더 정확한 채널추정과 간섭제거 효과를 제공한다. 배열 안테나의 수가 여섯 개 이상인 경우, 복합형 빔 성형 방식은 빔 수신 각 범위(AOS: Angle-of-Spread)가 30°이하에서 일반적인 MRC 빔 성형 방식보다 더 좋은 성능을 보인다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.2078-2082
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• 2009

Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, stream bank stabilization methods, and stream flow processes are described and interpreted for selected stream of Goesan, Central Korea. Idong Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods. The project aim to maintain or increase stream bank stabilization ecosystem goods and services while protecting downstream and stream bank ecosystem. A number of protecting methods which are a Flight of fieldstone, Vegetation block, Green river block, Stone net, Green environment block, Eco friendly cobble, Vegetation mat and Geo green cell and Firefly block were applied on the bank of Idong stream. The stream sites have been monitored about flora conditions each method in 2007. We selected 12 points for summer seasons to separately investigate in left bank, right bank and river bed. The main purpose of this study was to find out suitable methods and to improve stream restoration techniques for ecosystem. On the stream bank, Eco friendly cobble method(9.57) was the highest average of vegetation cover and Firefly block method(3.87) was the lowest average in applied methods.

• Journal of Communications and Networks
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• 제12권2호
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• pp.140-149
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• 2010

Green communication is a new paradigm of designing the communication system which considers not only the processing performance but also the energy efficiency. Power control management is one of the approaches in green communication to reduce the power consumption in distributed communication system. In this paper, we propose improved power control schemes for mobile satellite systems with ancillary terrestrial components (ATCs). In order to increase system capacity and reduce the transmitting power of the user's equipment, we propose an efficient channel estimation method consisting of a modified open-loop power control (OLPC) and closed-loop power control (CLPC). The OLPC works well if the forward and reverse links are perfectly correlated. The CLPC is sensitive to round-trip delay and, therefore, it is not effective in a mobile satellite system. In order to solve the above problem, we added monitoring equipment to both the OLPC and CLPC to use information about transmitting power that has not yet been received by the receiver over the satellite/ATC channel. Moreover, we adapted an efficient pilot diversity of both OLPC and CLPC in order to get a better signal to interference plus noise ratio estimation of the received signal.

• 한국BIM학회 논문집
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• 제4권4호
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• pp.1-12
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• 2014

As interest for visualization and real time processing of construction management information was heightened recently, a diversity of management tools have been developed and corresponding systems also have been changed. In the case of BIM(Building Information Modeling) which is being spotlighted as such kind of management tool, its outcome such as technical innovation and time saving through overseas success case, reducing effect of unnecessary work, and so forth has continuously been established. The BIM in which various information related with life cycle of project are managed with the base of 3D object is useful as an information management tool of construction project which becomes complex and large in its scale. The aim of this paper is analysis or reliability on BIM design for expressway. To solve these issues, this study analyzes the design document, road design handbook, guide. Also this paper performed analysis of reliability 2D vs. BIM quantity calculation. This pilot projects "BIM design at Daegu expressway Lot No.5" lays the foundation for future work on BIM based civil engineering design.