• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.2
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• pp.95-100
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• 2005

In order to improve the gill nets for croaker, Miichthys miiuy which is proper to the fishermen's income ans fisheries resource management, we had studied to the net height of present gill nets (mesh size 160mm, 50 mesh in depth), experimental gill nets-I(mesh size 150mm, 68 mesh in depth) and experimental gill nets-II(mesh size 142mm, 75 mesh in depth) in wter using the gill nets design ans analysis simulation system, and then investigated and analyzed the catch efficiency of each gill nets through the field fishing experiments. The net height of emperimental gill nets-I and experimental gill nets-II in water were estimated respectively about 1.5 times and 1.3 times higher than present gill nets which the net height is about 3.5m as the results of simulation considering the current of fishing fields. Total number of croakers which were caught by the persent gill nets was 62(body length 300~1,200mm), total catch weight was 398.7kg (mean 0.6kg/sheet). Total number of croakers which were caught by the experimental gill nets- I was 68(body length 600~1,100mm), total catch weight was 391.6kg (mean 1.2kg/sheet). Total number of croakers which were caught by the experimental gill nets-II was 28(body length 400~900mm), total catch weight was 99.2kg (mean 0.3kg/sheet).

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.403-406
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• 1997

This paper presents a Petri net approach for the control and monitoring of discrete event system. The proposed model is fuzzy Petri nets based on the fuzzy logic with Petri nets and the hierarchy concept. Fuzzy Petri nets have been used to model the imprecise situations which can arise within automated manufacturing system, and also the hierarchy concept allow to handle the refinement of places and transition in Petri nets model. These will form the foundation of a simulator-tool with manipulation interface for application of fuzzy Petri nets.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.27-32
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• 2022

The fifth generation (5G) mobile communication technology is designed to meet all communication needs. Heterogeneous networks (HetNets) are a new emerging network structure. HetNets have greater potential for radio resource reuse and better service quality than homogeneous networks since they can evolve small cells into macrocells. Effective resource allocation techniques reduce inter-user interference while optimizing the utilization of limited spectrum resources in HetNets. This article discusses resource allocation in 5G HetNets. This paper explains HetNets and how they work. Typical cell types in HetNets are summarized. Also, HetNets models are explained in the third section. The fourth component addresses radio resource control and mobility management. Moreover, future study in this subject may benefit from this article's significant insights on how HetNets function.

• Fisheries and Aquatic Sciences
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• v.6 no.1
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• pp.34-40
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• 2003

Three panel trammel nets were made illegal for the brown shrimp (Penaeus japonicus) or fishes by Korean fisheries law while trammel nets for fleshy prawn in the West sea remained legal. In this study a single panel tangle net with vertical loop lines rigged between the float line and sinker line was specially designed to catch brown shrimp. This net was developed for the first time after observation of the brown shrimp behaviour when reacting to a net in an observation tank. In field experiments these single tangle nets were compared with the traditional trammel nets in the coastal waters of the Keoje area. The mean number of the brown shrimp for 53 fishing operations was 1.13 per unit panel of the single tangle nets when fitted with the vertical loop lines. This was $84\%$ of the mean catch of 1.36 achieved with the trammel nets. These results of fishing experiments using single tangle nets in the field revealed a high fishing efficiency for the brown shrimp and showed little difference from trammel nets. The size of the brown shrimp or number of by-catch was not different between single tangle nets and trammel nets.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.1
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• pp.1-9
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• 2011

In order to investigate the cause and magnitude of scale effect occurring in the model experiments of fishing nets, five pairs of Nylon pyramid nets and one pair of PE ones in which all the two nets paired were equal each other in the factors determining their flow resistance, i. e., the ratio d/l of diameter d to length l of bars, the angle f between two adjacent bars, the attack angle q of nettings to the water flow, and the wall area S of nets, and different in the values of d and l were prepared. Then, the nets were attached to the circular steel frame alternately and their flow resistances with shapes in water were measured on the sea ascribing no turbulent flows by using the tension meter made of a block bearing for the experiment. All the Nylon nets were spreads out easily in water to form a circular cone at relatively low velocity of water and showed the resistance smaller a little in the nets with larger d and l than them with smaller d and l, because the filtration of water through meshes become easier in nets especially with larger l. But PE nettings were not spread out sufficiently on account of their small flexibility and showed higher resistance especially in them with thicker twines. Therefore, the difference in bar length or mesh size and flexibility of nettings between prototype and model nets are regarded to become factors ascribing scale effect. Especially the influence of the difference in mesh size may become large significantly in actual model experiments because the mesh size of model nets is decided at much larger value than that given by scale ratio and so the difference of mesh size between the two nets become much larger than that between nets used in this experiment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.2
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• pp.95-105
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• 2013

Physical characteristics of net filament were investigated to test the fishing capacity of gill nets due to the flexibility difference between nylon and biodegradable nets (PBS 95%+PBAT 5% and PBS 80%+PBAT 20%). In addition, a total of 16 fishing experiments were conducted in the coastal waters of Jeongja, Ulsan, from August 10 to October 20, 2011 and from September 11 to November 3, 2012. The test results showed that nylon net filament exhibited more flexibility than biodegradable net filament when they were wet. Accordingly, the longer submerged time, the more fishing capacity the nylon gill nets demonstrated in comparison with the biodegradable gill nets. A total of 16 species were caught in 2011 with the nylon gill nets (1,323 fishes, weighing 342,885g) and the biodegradable gill nets (958 fishes, weighing 236,857g). 15 species were caught in 2012 with the nylon gill nets (1,582 fishes, weighing 448,360g) and the biodegradable gill nets (1,431 fishes, weighing 406,590g). Thus catch weights and the number of fish caught produced by the nylon nets were 1.45 times and 1.38 times higher than those of the biodegradable nets produced in 2011, and 1.1 times and 1.11 times higher in 2012. A test on the target species, pointhead flounder (Cleisthenes pinetorum) has similar results. The flexibility of a net was proved to be related to the fishing capacity, and as a result, it is concluded that the higher flexibility, the higher fishing capacity.

• Ocean and Polar Research
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• v.29 no.1
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• pp.81-86
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• 2007

Abandoned fishing nets served Little Tern(Sterna albifrons) chicks as cover on a sandy island on Ganwol Lake, Hongsung-gun, Chungcheongnam-do, Korea. Chicks were incidently caught in $2.5cm{\times}2.5cm$ mesh sized nets and died of dehydration and exhaustion. Three adults died when they were caught by abandoned fishing net during parental care period in $2.5cm{\times}2.5cm$ mesh sized nets. Whereas $0.7cm{\times}0.7cm$ mesh sized nets did not affect the chicks' or adults' survival. Overlapped nets with several layers were more dangerous for chicks than were spread nets with a single layer. Dead chicks and adults were found to have been entangled by wing and neck. In this study, wing and nape(head+bill) of dead chicks were longer than those of live chicks. To improve the survival rate of Little Tern chicks at Ganwol Lake, abandoned fishing nets must be removed before the breeding season.

• Journal of KIISE:Software and Applications
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• v.27 no.3
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• pp.210-216
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• 2000

Place/Transition(P/T) nets has been used in protocol verification and concurrent system verification since it is suitable for describing concurrency and provides several well-established verification techniques. And it has been used as a base formalism for such high-level Petri nets as colored Petri nets, object-oriented Petri nets and etc. However, when analyzing complex models using P/T nets and P/T nets-based high-level Petri nets, there may be state explosion in reachability analysis due to improper handling of concurrency. In this paper, we define a structural concurrency in P/T nets, propose a partitioning algorithm based on the detected structural concurrency, and provide analysis techniques for such properties as boundedness of places and liveness of transitions, which are performed on compositional reachability graphs. The analysis techniques based on Petri net slices can be used in efficiently analyzing P/T nets-based high-level Petri net models as well as P/T net models.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7431-7434
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• 2015

As an important component of innate immune system, neutrophil has been involved in many other physiological processes, including tumor-related diseases. In 2004, the phenomenon of NETs was reported for the first time. Extracellular decondensed chromatin, released from activated neutrophils, forms a network structure, which is NETs. This review focuses on the function of NETs in tumor cell proliferation, metastasis, and tumor-associated thrombosis; it also explores the application of NETs specific markers in the diagnosis of pre-thrombotic state and tumor associated diseases; it also explores NETs inhibitor for the treatment of tumor-related diseases. In view of the rapid development of NETs, it may provide new therapeutic targets for tumor-associated thrombosis, and even tumor itself.

• Journal of the Korea Society for Simulation
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• v.11 no.2
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• pp.77-88
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• 2002

Petri nets is a widely used formalism for specification and analysis of concurrent systems which is a subclass of discrete event systems. The DEVS (Discrete Event System Specification) formalism provides a general framework for specification of discrete event systems in a hierarchical, modular form. Often, modeling a discrete event system may employ both Petri Nets and DEVS formalism. In such a case low-level operational logics are modeled by Petri Nets and high-level managements by the DEVS formalism. Analysis of the system requires simulation of the overall system. This paper presents an algorithm for transformation of Petri Nets to DEVS formalism. The transformation enables modelers to simulate an overall system, which consists of DEVS models and Petri Nets models, in a unified DEVS simulation environment such as DEVSim++. An example for such transformation will be given.