• Title, Summary, Keyword: Set net

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Deadlock Analysis and Control of FMS's Using Siphon property (Siphon 특성을 이용한 FMS의 Deadlock 해석과 제어)

  • Kim, Jung-Chul;Kim, Jin-Kwon;Hwang, Hyung-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.7
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    • pp.677-682
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    • 2007
  • Concurrent competition for finite resources by multiple parts in flexible manufacturing systems(FMS's) and inappropriate initial marking or net structure of Petri net with share resources results in deadlock. This is an important issue to be addressed in the operation of the systems. Deadlock is a system state so that some working processes can never be finished. Deadlock situation is due to a wrong resource allocation policy. In fact, behind a deadlock problem there is a circular wait situation for a set of resources. Deadlock can disable an entire system and make automated operation impossible. Particularly, an unmanned system cannot recover from such a status and a set of jobs waits indefinitely for never-to-be-released resources. In this paper, we proposed a deadlock prevention method using siphon and trap of Petri net. It is based on potential deadlock which are siphon that eventually became empty. This method prevents the deadlock by the control of transition fire and initial marking in the Petri net. An given example of FMS is shown to illustrate our results with deadlock-free.

Development of Delaunay Triangulation Algorithm Using Oct-subdivision in Three Dimensions (3차원 8분할 Delaunay 삼각화 알고리즘 개발)

  • Park S.H.;Lee S.S.
    • Korean Journal of Computational Design and Engineering
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    • v.10 no.3
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    • pp.168-178
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    • 2005
  • The Delaunay triangular net is primarily characterized by a balance of the whole by improving divided triangular patches into a regular triangle, which closely resembles an equiangular triangle. A triangular net occurring in certain, point-clustered, data is unique and can always create the same triangular net. Due to such unique characteristics, Delaunay triangulation is used in various fields., such as shape reconstruction, solid modeling and volume rendering. There are many algorithms available for Delaunay triangulation but, efficient sequential algorithms are rare. When these grids involve a set of points whose distribution are not well proportioned, the execution speed becomes slower than in a well-proportioned grid. In order to make up for this weakness, the ids are divided into sub-grids when the sets are integrated inside the grid. A method for finding a mate in an incremental construction algorithm is to first search the area with a higher possibility of forming a regular triangular net, while the existing method is to find a set of points inside the grid that includes the circumscribed sphere, increasing the radius of the circumscribed sphere to a certain extent. Therefore, due to its more efficient searching performance, it takes a shorer time to form a triangular net than general incremental algorithms.

Entering and Leaving Behaviour of Fish Schools to Set-net in the Coast of Cheju Island (제주도 연안 정치망에 입·출망하는 어군의 행동)

  • Kim, Seong-Hyun;Kim, Mun-Kwan;Kim, Suk-Jong;Park, Jeong-Sik
    • Journal of Fisheries and Marine Sciences Education
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    • v.10 no.2
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    • pp.211-225
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    • 1998
  • A field experiment was carried out for fishes on entering time to a set-net, swimming speed, current speed and direction at the Dongbok-Ri coast on Cheju Island. The results of the experiment are as follows : 1. The observation results from 07:00 to 18:00 showed that coral fish, flying fish, horse mackerel, drub mackerel and striped mullet enter the set-net from 07:00 to 14:00 mainly. 2. From the result of analyzing relationships between entering time and tide, coral fish and horse mackerel tend to enter the set-net on turn of tidal current and ebb respectively. 3. The leaving rates of coral fish, flying fish, drub mackerel, and striped mullet from the set-net were 13%, 45%, 50%, and 100%, respectively but all horse mackerel remained in the net. 4. The swimming speed of coral fish, flying fish, horse mackerel and drub mackerel are 5~25cm/sec, 20~50cm/sec, 15~45cm/sec and 10~30cm/sec, respectively and their dominant speeds are 10~15cm/sec(55%), 30~35cm/sec(30%), 30~40cm/sec(60%), and 15~20cm/sec(60%), respectively.

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Composition and Catch Variation of Fisheries Resources by Set Net in the Mizo Fishing Ground off Namhae Island (남해도 미조 정치망 어장의 출현 종과 어획량 변동특성)

  • Cha, Byung Yul
    • Korean Journal of Ichthyology
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    • v.21 no.3
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    • pp.191-199
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    • 2009
  • Fisheries resources collected by set net in the Mizo fishing ground off Namhae Island were studied from March to December 2004 to determine species composition and catch variation. The water temperature of the fishing ground ranged $10.9{\sim}25.1^{\circ}C$ A total of 69,147.5 kg comprising 39 species was caught during the survey period. Most of the catch was fishes (33 species); others included cephalopods (5 species) and crustaceans (1 species). The dominant species were migratory, such as Trichiurus lepturus, Ammodytes personatus, Engraulis japonicus, and Scomberomorus niphonius, and accounted for 81.2% of the total catch. Sub-dominant species were Sardinops melanostictus, Acanthopagrus schlegeli, shrimps, and Todarodes pacificus, but they accounted for only 12.1% of the total. The catch by set net during the fishing period was much higher in spring and in autumn than in summer, relating to the recruitment of dominant species. Although the number of species had a tendency to decreased after summer, the catch in autumn was also higher than that in spring due to high temperatures (>$17^{\circ}C$ and seasonal variation of dominant species. The dominant species in spring were A. personatus and E. japonicus and in autumn were T. lepturus, S. niphonius, and E. japonicus.

An Estimation of production Function in the Coastal Fishing (연안어선어업의 생산함수추정)

  • 김기수;강용주
    • The Journal of Fisheries Business Administration
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    • v.24 no.2
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    • pp.69-82
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    • 1993
  • The purpose of this paper is to estimate production function in the coastal fishing, especially long bag set net fishing and trap fishing using Cobb-Douglas production function with the three main variables: fishing quantity per tonage(WQFP), the number of working persons per tonage(WEMP), and the number of utilized fishing equipments per tonage(WEQU). The statistical results of such estimation reveal that fishing quantity per tonage can be expressed as a function of the number of working persons per tonage and the number of utilized fishing equipments per tonage. The estimated coefficients of WEMP and WEQU are statistically significant and also satisfy the requirements of Cobb-Douglas production function. This study also estimates marginal rate of technical substitution of labor in terms of capital (MRT $S_{LK}$ )in each long bag set net fishing and trap fishing. The resuits of this study show us that trap fishing has the technical characteristic of constant returns to scale(CRS) but long bag net fishing has that of decreassing returns to scale(DRS).

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Scheduling of flexible manufacturing systems with the consideration of tool set-up times (공구셋업시간을 고려한 유연생산시스템의 스케쥴링)

  • Yim, Seong-Jin;Lee, Doo-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.1
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    • pp.90-101
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    • 1998
  • This paper presents a scheduling method that uses Petri net modeling and heuristic search to handle the tool setup. In manufacturing systems, a tool is attached to a particular machine to process a particular operation. The activity to attach a tool to a particular machine and detach the tool from the machine requires time. The processing time of operations varies according to the attached tool and the machine used. The method proposed in this paper uses Petri net to model these characteristics and applies a search algorithm to the reachability graph of the Petri net model to generate an optimal or near-optimal schedule. New heuristic functions are developed for efficient search. The experimental results that show the effectiveness of the proposed method are presented.

Ontology Mapping using Semantic Relationship Set of the WordNet (워드넷의 의미 관계 집합을 이용한 온톨로지 매핑)

  • Kwak, Jung-Ae;Yong, Hwan-Seung
    • Journal of KIISE:Databases
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    • v.36 no.6
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    • pp.466-475
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    • 2009
  • Considerable research in the field of ontology mapping has been done when information sharing and reuse becomes necessary by a variety of ontology development. Ontology mapping method consists of the lexical, structural, instance, and logical inference similarity computing. Lexical similarity computing used in most ontology mapping methods performs an ontology mapping by using the synonym set defined in the WordNet. In this paper, we define the Super Word Set including the hypenym, hyponym, holonym, and meronym set and propose an ontology mapping method using the Super Word Set. The results of experiments show that our method improves the performance by up to 12%, compared with previous ontology mapping method.

Seasonal Variation of Abundance and Species Composition of Fishes Caught by a Set Net in the Coastal Waters off Yosu, Korea (여수연안 정치망 어획물의 종조성과 계절변동)

  • KIM Yeong Hye;KIM Jong Bin;CHANG Dae Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.2
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    • pp.120-128
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    • 2003
  • Fishes were caught by a set net in the coastal waters off Yosu, Korea from April to October, 2001, and seasonal variation of abundance and species composition were studied. Fifty two species were identified as fish $(89\%)\;cephalopods\;(10\%)\;and\;crustaeans\;(1\%).$ Of the fishes Engraulis japonicus, Trachurus japonicus and Trichiurus lepturus were dominant species representing $64.1\%$ in total number of individuals. The number of species was high in spring and low in summer; number of individuals was high in spring and low in autumn. The diversity index (H') was 0.4-0.7 The abundance and species composition fluctuated seasonally. Occurrence of the various stages of fishes indicated that Scombia japonicus, T. japonicus and E japonicus utilized in the area as spawning ground, Conger myriaster larvae, Ammodytes personatus and Seriola quinqueradiata as nursery ground, and T. lepturus and Ilisha elongata as spawning and nursery grounds.

Tracking of an Individual Fish by Use of the Ultrasonic Tag (초음파표식에 의한 단체어의 행동 추적)

  • 신형일
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.25 no.2
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    • pp.54-60
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    • 1989
  • This paper described on the tracking of an individual fish at the fishing ground of set net by use of a small ultrasonic fish tag. The apparatuses used were composed with a tag, three receivers and two time-interval counter oscilloscope. A pulsed ultrasonic transmitter tag fitted to back of a dorsal fin of a yellowtail specimen, Seriola quinqueradidta TEMMINCK et SCHLEGEL is tracked by measuring differences in the time of arrival of the acoustic pulses at an arrangement of three receivers in the freeding tank. The successive positions of the fish were calculated from the differences in the received time of the signals. A fish carying the tag was tracked in the fishing ground of set net by use of the hydrophone and Loran-C. The results of the tests showed that this method gave good positional information to track the movement of an individual fish in the fishing ground of set net.

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Fundamental Studies on the Migrating Course of Fish Around the Set Net ( 3 ) - Statistic Analysis for the Catch of Set Net - (정치망어장의 어도형성에 관한 기초연구 ( 3 ) - 어획자료의 통계적 분석 -)

  • Lee, Ju-Hui;Yeom, Mal-Gu;Park, Byeong-Su
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.24 no.2
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    • pp.71-77
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    • 1988
  • The authors analyzed the daily catch data which were obtained from two different regions at the Southern Sea in Korea, Neungpo, Geoje island and Yangwhagum, Namhae island, during three or four years in 1978, 1981-1985, in order to know the fishing characteristics of the set net fisheries. The favorable fishing season was summer in the southern sea. The total catches during one year were greatly affected by those several day when the dominant species of fish were caught in large quantities. The dominant species of fish at Neungpo were little horse mackerel, sand lance, sardine, hair tail, spanish mackerel and common mackerel, and those at Yangwhagun were anchovy, little horse mackerel, sardine, spanish mackerel and gizzard shad, in order of catch. Especially, the little horse mackerel and the sardine appeared to make up very big schools at both Neungpo and Yangwhagum. The occurrence seasons of the dominant species were different by the region, but generally those were earlier at western part than at eastern part of the Southern Sea in Korea.

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