• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.41-44
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• 2001

In this paper, we have investigated the adaptive sector antenna which can control the size and direction angle of sectors, and proposed the three sectorization algorithms which are based on distribution of users, distribution of codes and distribution of signal power, respectively. The BERs of each sectorization algorithms are compared through computer simulation. As results of the simulation, the sectorization algorithm based on signal power are better than the other in terms nf BER. We have simulated error performance the DS-CDMA/BPSK system with the antenna in AWGN, frequency non-selective Rayleigh fading and MAI channels.

• 한국통신학회논문지
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• 제40권6호
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• pp.997-1004
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• 2015

이 논문에서는 MISO 하향 능동 안테나 시스템에서 수직 분할 기법을 연구하였다. 능동 안테나 시스템에서는 각 섹터에서 안테나 빔 패턴을 조절 가능 할 뿐만 아니라 복수의 수직 안테나 빔을 통해 수직 섹터분할도 가능하다. 수직 섹터 분할을 위한 최적 빔 기울기를 구하기 위해 기존의 전역 탐색 기법은 매우 높은 계산 복잡도를 요구하기 때문에 이 논문에서는 이러한 계산 복잡도를 낮추기 위해 두 가지 알고리즘을 제안하였다. 먼저 불규칙 행렬이론에서의 광범위 시스템 근사치를 이용하여 근사 전송률 합에 기반을 둔 알고리즘을 제안하였다. 또한, 기존의 하나의 섹터 전송 기법에서의 결과를 이용한 폐쇄 형태 표현을 가진 알고리즘도 제안하였다. 실험결과를 통해 제안된 알고리즘들이 기존의 전역 탐색 알고리즘에 비해 복잡도를 매우 감소시킴에도 불구하고 거의 비슷한 성능을 가짐을 확인하였다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.11-11
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• 2018

Cryphonectria parasitica, chestnut blight fungus, has a characteristic of decreasing pathogenicity when infected with Cryphonectria hypovirus 1. C. parasitica is known to be one of the most representative model systems used to observe the interaction between viruses, plants and fungi. The mitogen-activated protein kinase (MAPK) pathway, which is well conserved in various organisms ranging from yeast to humans, functions in relaying phosphorylation-dependent signals within MAPK cascades to diverse cellular functions involved in the regulation of pheromone, cell wall integrity, and osmotolerance in filamentous fungi. Several genes in the MAPK pathway were revealed to be regulated by hypovirus, or to be involved in pathogenicity in C. parasitica. Among these pathways, the CWI pathway has aroused interest because CpBck1, an ortholog of yeast Bck1 (a CWI MAPKKK), was previously reported to be involved in cell wall integrity and sectorization. Interestingly, sporadic sectorization was observed in the CpBck1 mutant and sectored phenotypes were stably inherited in the progeny that were successively transferred from sectored mycelia. In this study, we analyzed the biological function of CpSlt2, downstream gene of CpBck1, to confirm whether the sectorization phenomenon occurred in the specific single gene or cell wall integrity (CWI) pathway. As results, the CpSlt2-null mutant exhibited marked changes in colonial growth, near absence of conidiation and aerial hyphae, abnormal pigmentation, CWI-related phenotypic defects, and dramatically impaired virulence. As cultivation of the mutant strains progressed, the majority of the colonies showed sporadic sectorization and mycelia from the sectored area stably maintained the sectored phenotype. These results suggest that the unique sectorization is CWI pathway-specific, though the components in the same CWI pathway have common and specific functions.

• Molecules and Cells
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• 제42권4호
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• pp.363-375
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• 2019

Fungal sectorization is a complex trait that is still not fully understood. The unique phenotypic changes in sporadic sectorization in mutants of CpBck1, a mitogen-activated protein kinase kinase kinase (MAPKKK) gene, and CpSlt2, a mitogen-activated protein kinase (MAPK) gene, in the cell wall integrity pathway of the chestnut blight fungus Cryphonectria parasitica have been previously studied. Although several environmental and physiological factors cause this sectoring phenotype, genetic variants can also impact this complex morphogenesis. Therefore, RNA sequencing analysis was employed to identify candidate genes associated with sectorization traits and understand the genetic mechanism of this phenotype. Transcriptomic analysis of CpBck1 and CpSlt2 mutants and their sectored progeny strains revealed a number of differentially expressed genes (DEGs) related to various cellular processes. Approximately 70% of DEGs were common between the wild-type and each of CpBck1 and CpSlt2 mutants, indicating that CpBck1 and CpSlt2 are components of the same MAPK pathway, but each component governs specific sets of genes. Functional description of the DEGs between the parental mutants and their sectored progenies revealed several key pathways, including the biosynthesis of secondary metabolites, translation, amino acid metabolism, and carbohydrate metabolism; among these, pathways for secondary metabolism and translation appeared to be the most common pathway. The results of this comparative study provide a better understanding of the genetic regulation of sector formation and suggest that complex several regulatory pathways result in interplays between secondary metabolites and morphogenesis.

• 한국통신학회논문지
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• 제39A권3호
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• pp.158-160
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• 2014

최근 능동 안테나의 발달로 수직적 섹터구분 기술이 적용된 LTE 시스템에서 다양한 빔 패턴을 사용하는 것이 가능하다. 본 논문에서는 시스템 레벨 시뮬레이터를 활용하여 시스템 성능을 분석하고, 최적 섹터 빔 조합 및 최적 파라미터를 제시한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.241-242
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• 2008

This paper proposes a sectorization and exclusive subcarrier allocation technique for dirty paper coding (DPC) aided orthogonal frequency division multiple access (OFDMA) multihop cellular networks. Simulation result shows that the proposed technique significantly increases the achievable sum rate compared to the conventional mobile station selection approach.

• 대한산업공학회지
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• 제26권2호
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• pp.155-164
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• 2000

Recently Fiber-optic Micro-cellular Wireless Network is considered to solve frequent handoffs and local traffic unbalance in microcellular systems. In this system, central station which is connected to several microcells by optical fiber manages the channels. We propose an efficient sectorization algorithm which dynamically clusters the microcells to minimize the blocked and handoff calls and to balance the traffic loads in each cell. The problem is formulated as an integer linear programming. The objective is to minimize the blocked and handoff calls. To solve this real time sectorization problem the Tabu Search is considered. In the tabu search intensification by Swap and Delete-then-Add (DTA) moves is implemented by short-term memory embodied by two tabu lists. Diversification is considered to investigate proper microcells to change their sectors. Computational results show that the proposed algorithm is highly effective. The solution is almost near the optimal solution and the computation time of the search is considerably reduced compared to the optimal procedure.

• 산업공학
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• 제19권1호
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• pp.1-8
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• 2006

The mobile communication network has to offer good quality of services (QoS), high capacity, and more coverage at a lower cost. However, with the increase of cellular user, the shortage of capacity due to unbalanced call distribution and lack of QoS are common. This paper deals with dynamic sectorization for efficient resource management to solve load unbalancing among microcells in CDMA (Code Division Multiple Access) microcellular system. Dynamic load balancing can be effected by grouping micro-cells properly and grouping can be developed through a routing mechanism. Therefore, we use ants and their routes to choose the optimum grouping of micro-cells into sectors using Multiple Ant Colony System (MACS)in this paper.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.65-68
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• 1999

In this paper the Wideband DS/CDMA system capacity variation is analyzed by the impact of imperfect sectorization and man-made noise, which is more predominant in urban area than thermal noise. In general man-made noise is increasing as the electronic machines are increasing nowadays. It shows that user capacity and cell radius variation are much sensitive by the man-made noise.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1996년도 추계종합학술발표회 논문집
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• pp.61-64
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• 1996