• Earthquakes and Structures
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• v.8 no.5
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• pp.1039-1054
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• 2015

The purpose of this study was to evaluate the seismic performance of weak-axis column-tree type connections used in steel moment frames. These connections are composed of a shop-welded and fieldbolted steel structure and can improve welding quality. On this basis, column-tree type connections are widely used in steel moment resisting frames in Korea and Japan. In this study, splices designed with a semirigid concept regarding the seismic performance of column-tree connections were experimentally evaluated. The structures can absorb energy in an inelastic state rather than the elastic state of the structures by the capacity design method. For this reason, the plastic hinge might be located at the splice connection at the weak-axis column-tree connection by reducing the splice plate thickness. The main variable was the distance from the edge of the column flange to the beam splice. CTY series specimens having column-tree connections with splice length of 600 mm and 900 mm were designed, respectively. For comparison with two specimens with the main variable, a base specimen with a weak-axis column-tree connection was fabricated and tested. The test results of three full-scale test specimens showed that the CTY series specimens successfully developed ductile behavior without brittle fracture until 5% story drift ratio. Although the base specimen reached a 5% story drift ratio, brittle fracture was detected at the backing bar near the beam-to-column connection. Comparing the energy dissipation capacity for each specimen, the CTY series specimens dissipated more energy than the base specimen.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.83-90
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• 2009

Wireless Sensor Network (WSN) is a wireless network that gathers information from remote area with autonomously configured routing path. We propose a fusion based routing for a 'convergecast' in which all sensors periodically forward collected data to a base station. Previous researches dealt with only full-fusion or no-fusion case. Our Fusion rate based Spanning Tree (FST) can provide effective routing topology in terms of total cost according to all ranges of fusion rate f ($0{\leq}f{\leq}1$). FST is optimum for convergecast in case of no-fusion (f = 0) and full-fusion (f = 1) and outperforms the Shortest Path spanning Tree (SPT) or Minimum Spanning Tree (MST) for any range of f (0 < f < 1). Simulation of 100-node WSN shows that the total length of FST is shorter than MST and SPT nearby 31% and 8% respectively in terms of topology lengths for all range of f. As a result, we confirmed that FST is a very useful WSN topology.

• Korean Journal of Organic Agriculture
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• v.18 no.4
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• pp.587-598
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• 2010

This study was carried out to elucidate the effects of mulching materials on the growth of potato and weed control at the experimental farm of Chungbuk National University from August 9 in 2008 to June 28 in 2009. Tested potato, cv. 'Superior', was grown under the different mulching materials such as pine tree leaf, oak tree leaf, rice straw, rice hull and sawdust, and control(non-mulching). We tested two times with autumn and spring culture season. The obtained results from this study were summarized as follows; There was significantly difference in plant height, stem length, leaf length, leaf weight and tuber weight in pine tree leaf mulching treatment in autumn season among the treatments. The dominant weeds were Echinochioa crus-galli var. fadmerntacca and Cyperus amvuricus in autumn culture season, while were Echinochioa crus-galli var. fadmerntacca and Digitaria sanguinalis in spring culture season. The appearance of weeds in all of mulching treatment was significant reduced compared to control. The soil moisture content was the highest in rice hull mulching treatment, and that of mulching treatments was significantly higher than control. The soil temperature of mulching treatments was lower than that of control by from $1.0^{\circ}C$to $2.8^{\circ}C$ in autumn season and from $0.7^{\circ}C$ to $2.3^{\circ}C$ in spring season. The soil temperature was low in the order of pine tree leaf, rice straw, oak tree leaf, rice hull, sawdust, and control.

• Annual Conference on Human and Language Technology
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• 1995.10a
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• pp.18-22
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• 1995

문서 검색 시스템의 도치 색인 파일은 저장 공간과 검색 시간을 줄이기 위해 색인어 사전과 문서번호를 위한 이진 도치 파일 또는 비트벡터로 구성할 수 있다. 비트벡터는 1의 값을 가지는 비트만 저장함으로써 압축이 가능하나, Bit tree 압축 방법은 block의 크기가 어떻게 결정되느냐에 따라 압축률이 달라진다. 본 논문에서는 비트벡터에 나타나는 1의 값을 가지는 비트의 개수에 의해 bit tree 압축에 대한 최적의 block 크기를 결정하는 방법을 했다. 최적의 block의 크기는 (전체 비트벡터의 크기 / 1의 개수)보다 작거나 같은 최대의 2의 승수이다. 또한 block내의 1의 값을 가지는 비트의 위치에 의해 상대 위치값을 계산해서 block의 오른쪽 반에 나타나는 비트를 더 압축할 수 있는 기법을 구현한다. 본 논문에서 구현한 압축 기법은 Run Length를 이용한 방법에 비해서 13.65%, 기존의 Bit Tree 방법에 비해서 1.88%의 압축률을 개선했다.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.515-518
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• 2005

LiDAR(Light Detection and Ranging) with digital aerial photograph can be used to measure tree growth factors like total height, height of clear-length, dbh(diameter at breast height) and crown projection area. Delineating crown is an important process for identifying and numbering individual trees. Crown delineation can be done by watershed method to segment basin according to elevation values of DSMmax produced by LiDAR. Digital aerial photograph can be used to validate the crown projection area using LiDAR. And tree height can be acquired by image processing using window filter$(3cell\times3cell\;or\;5cell\times5cell)$ that compares grid elevation values of individual crown segmented by watershed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.27-37
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• 2005

The rectilinear Steiner tree problem (RSTP) is to find a minimum-length rectilinear interconnection of a set of terminals in the plane. It is well known that the solution to this problem will be the minimal spanning tree (MST) on some set Steiner points. The RSTP is known to be NP-complete. The RSTP has received a lot of attention in the literature and heuristic and optimal algorithms have been proposed, A key performance measure of the algorithm for the RSTP is the reduction rate that is achieved by the difference between the objective value of the RSTP and that of the MST without Steiner points. A hybrid evolution strategy on RSTP based upon the Prim algorithm was presented. The computational results show that the evolution strategy is better than the previously proposed other heuristic. The average reduction rate of solutions from the evolution strategy is about 11%, which is almost similar to that of optimal solutions.

• Journal of Plant Biology
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• v.34 no.3
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• pp.191-199
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• 1991

This study has been conducted to investigate the developmental changes of cambial initials and their derivatives in relation to the growing girth of tree in Diosypros kaki and Firmiana simplex. In D. Kaki and F. simplex with typical storeyed cambium, increase in the girth of camium occurred by radial anticlinal division in general, however occasionally the increase was companied by pseudotransverse division. The length of fusiform initials, vessel member, and sieve tube member remained relatively constant throughout the secondary growth but that of fiber showed general tendancy to increase with growing girth of tree. During the girth increase of tree, height and number of ray remained constant in D. kaki, however in F. simplex, height of ray markedly decreased while the number of ray per unit area more or less increased. The secondary ray was originated from the segmentation or division of the side or end of fusiform initials.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.1056-1064
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• 2003

The Euclidean steiner tree problem (ESTP) is to find a minimum-length euclidean interconnection of a set of points in the plane. It is well known that the solution to this problem will be the minimal spanning tree (MST) on some set steiner points, and the ESTP is NP-complete. The ESTP has received a lot of attention in the literature, and heuristic and optimal algorithms have been proposed. In real field, heuristic algorithms for ESTP are popular. A key performance measure of the algorithm for the ESTP is the reduction rate that is achieved by the difference between the objective value of the ESTP and that of the MST without steiner points. In recent survey for ESTP, the best heuristic algorithm showed around $3.14\%$ reduction in the performance measure. We present a evolution programming (EP) for ESTP based upon the Prim algorithm for the MST problem. The computational results show that the EP can generate better results than already known heuristic algorithms.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.4
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• pp.42-49
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• 2003

The branch and bound techniques based on cut tree and eigenvector have been Introduced in the literature [1, 2, 3, 6, 9, 12]. These techniques are used as a basis to allocate departments to floors and then to fit departments with unchangeable dimensions into floors. Grouping algorithms to allocate departments to each floor are developed and branch and bound forms the basis of optimizing using the criteria of rectilinear distance. The proposed branch and bound technique, in theory, will provide the optimal solution on two dimensional layout. If the runs are time and/or node limited, the proposed method is a strong heuristic The technique is made further practical by the fact that the solution is constrained such that the rectangular shape dimensions length and width are fixed and a perfect fit is generated if a fit is possible. Computational results obtained by cut tree-based algorithm and eigenvector-based algorithm are shown when the number of floors are two or three and there is an elevator.

• Journal of Plant Biology
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• v.33 no.3
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• pp.153-158
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• 1990

The structural changes in the vascular cambium and secondary xylem Alnus hirsuta (SPACH) Rupr. have been investigated in relation to the girth of the tree. The fusiform initials gain a gradual size increase and later remain more or less constant in their length and width. The width of the ray initials remain constant but their heights gradually increase before becoming almost constant. Xylem elements undergo considerable changes in their dimension with the growing girth of the tree and their trends of structural changes are the same as those of cambium.