• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.255-267
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• 2004

This study was conducted in order to improvement of fishing gear and fishing operating system for anchovy boat seine by bag net A-type and B-type was attached with half size modified nets. Field experiments were carried out observe geometry of nets by catcher boats. The obtained results are summarized as follows : The actual ratio of net opening in each part of the half size modified nets was increased from fore part to back part of the nets as shown the smallest value about 20% in wing net and the biggest value about 110% in bag net. In addition, vertical net opening of B-type net as measured as 10.9~11.8m in fore bag net and 5.8~8.0m in after bag net were 1~2m greater than 9.0~13.6m of A-type one, and 2~3m less than 9.3~10.4m of A-type one, respectively. Vertical net opening of half size modified net was shown as less variation of towing depth from wing net to inside wing net than those of traditional nets due to stable vertical performance. The mesh distortion or drift and variation of vertical net opening were decreased by improvement of bag nets in order to minimized shape of net pocket phenomenon whenever towing speed is slow. Bag net B-Type attached with dual flapper was shown as less variation in width of bag net and less escapement of anchovy.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.248-255
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• 2011

An investigation has been carried out, by computer simulation, to evaluate the impact of dispersion compensation configurations on 960 Gbps wavelength division multiplexed (WDM) system with optical phase conjugator (OPC). The considered dispersion compensation configurations in this research are conventional one-end type and bi-end type. One-end and bi-end type are made by using one dispersion compensating fiber (DCF) and two DCFs to decrease dispersion accumulated in one single mode fiber (SMF) span, respectively. It is found that bi-end compensation configuration offers the equal performance with that of one-end configuration in WDM system with residual dispersion per span (RDPS) of 400 ps/nm if net residual dispersion (NRD) had to be optimized in each cases.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.971-974
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• 2002

Petri net is an effective modeling tool for concurrent systems. Liveness problem is one of analysis problems in Petri net theory verifying whether the system is free from any local deadlocks. It is well known that computational complexity of liveness problem of general Petri net is deterministic exponential space. Some subclasses, such as marked graph and free choice net, are suggested where liveness problem is verified in less complexity. This paper studies liveness of siphon containing circuit (SCC) net. Liveness condition based on algebraic inequalities is shown. Then polynomial time decidability of liveness of SCC net is derived, if the given net is known to be an SCC net a priori.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.3
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• pp.200-207
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• 2013

Petri Nets are a system description and analysis tool. Reachability is one of the most basic properties in Petri Net research. In a sense, reachability research is the foundation study for other dynamic properties of Petri Nets through which many problems involving Petri Nets can be described. Nowadays, there are two mature analysis methods-the matrix equation and the reachability tree. However, both methods are localized, i.e., it is difficult to find a general algorithm that can determine reachability for an arbitrary Petri Net, especially an unbounded Petri Net. This paper proposes and proves three propositions in order to present a subclass of a Petri Net, the live single-branch Petri Net, whose reachability is equivalent to the satisfiability of the state equation.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3943-3948
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• 2022

Single-photon emission computed tomography is one of the reliable pin-by-pin verification techniques for spent-fuel assemblies. One of the challenges with this technique is to increase the total fuel assembly verification speed while maintaining high verification accuracy. The aim of the present study, therefore, was to develop an artificial intelligence (AI) algorithm-based tomographic image analysis technique for partial-defect verification of fuel assemblies. With the Monte Carlo (MC) simulation technique, a tomographic image dataset consisting of 511 fuel-rod patterns of a 3 × 3 fuel assembly was generated, and with these images, the VGG16, GoogLeNet, and ResNet models were trained. According to an evaluation of these models for different training dataset sizes, the ResNet model showed 100% pattern estimation accuracy. And, based on the different tomographic image qualities, all of the models showed almost 100% pattern estimation accuracy, even for low-quality images with unrecognizable fuel patterns. This study verified that an AI model can be effectively employed for accurate and fast partial-defect verification of fuel assemblies.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.368-377
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• 2014

Small yellow croaker is one of the important stocks in Korean waters. In this study, we conducted sea trials to estimate optimum height of a drift gill net for effective fishing of small yellow croaker. In the trial using existing net which has 9.2m in height, there was 22 species (1,180 fishes, 99.9kg) caught. The catch (in individuals) of small yellow croaker, especially larger fishes (over 22cm in FL), was higher as part of net height is higher, while the number of species bycaught and the catch of those species were higher as part of net height is lower. In the trial using extension net which has 18.4m in height, there was 27 species (2,030 fishes, 151.7kg). It showed same pattern with existing net in the section I to III, however, in the section IV which is over 13.8m of net height, the catch sharply decreased. The number of species bycaught and the catch of those species using extension net were also same as results using existing net. It showed that section III (9.2-13.8m) where is upper-middle part of the net has caught most of catch and large fishes having over 22cm in length. Through these results, it is judged that the setting depth of the net where is 4.6-13.8m above the sea bottom is the best to reduce bycatch and catch much more large size fishes, and the catch per net is proportional to filtering area of net. Therefore the Fisheries Resource Management Act (the clause 1, article 10) on the amount of usage for offshore drift gill net need to be considered not only length of a net but also net height.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.53-59
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• 2017

Optical character recognition (OCR) automatically recognizes text in an image. OCR is still a challenging problem in computer vision. A successful solution to OCR has important device applications, such as text-to-speech conversion and automatic document classification. In this work, we analyze character recognition performance using the current state-of-the-art deep-learning structures. One is the AlexNet structure, another is the LeNet structure, and the other one is the SPNet structure. For this, we have built our own dataset that contains digits and upper- and lower-case characters. We experiment in the presence of salt-and-pepper noise or Gaussian noise, and report the performance comparison in terms of recognition error. Experimental results indicate by five-fold cross-validation that the SPNet structure (our approach) outperforms AlexNet and LeNet in recognition error.

• Journal of the Korea Society for Simulation
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• v.12 no.1
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• pp.1-10
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• 2003

Recently, various network protocols have been developed to keep step with the rapid growth of Internet users. For the education of students in the computer networks classes, there have been many attempts to allow students experiment routers setting, operations and management of networks by themselves, in addition to the classroom lectures based on textbooks. One of the attempts is to install expensive real router experiment sets in laboratories for students, and one another is using router and network simulators for virtual experiments. This paper presents the design and implementation of NetSim, a scalable, component-based simulator environment for the network experimentation. NetSim expands the existing component-based JavaSim simulation tool for the education purpose, and it allows the design and experiment of various networks and protocols. For the evaluation of NetSim, it is shown that the network design and RIP-based router setting process is possible in NetSim.

• Smart Media Journal
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• v.12 no.7
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• pp.52-58
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• 2023

Alzheimer's disease is one type of dementia, the symptoms can be treated by detecting the disease at its early stages. Recently, many computer-aided diagnosis using magnetic resonance image(MRI) have shown a good results in the classification of AD. Taken these MRI images and feed to Free surfer software to extra the features. In consideration, using T1-weighted images and classifying using the convolution neural network (CNN) model are proposed. In this paper, taking the subjects from ADNI of subcortical and cortical features of 190 subjects. Consider the study to reduce the complexity of the model by using the single layer in the Res-Net, VGG, and Alex Net. Multi-class classification is used to classify four different stages, CN, EMCI, LMCI, AD. The following experiment shows for respective classification Res-Net, VGG, and Alex Net with the best accuracy with VGG at 96%, Res-Net, GoogLeNet and Alex Net at 91%, 93% and 89% respectively.

• Journal of Fisheries and Marine Sciences Education
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• v.6 no.1
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• pp.11-19
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• 1994

The North Pacific midwater trawling which is one of the important fishing methods for Korean fishing industry is working in the Bering Sea and the sea near Kamchaka Peninsula. The catch by Korean midwater trawlers had been recorded about 300 thousands $^{M/_T}$ a year. Six types of midwater trawl net-ordinary midwater trawl net, super-V trawl net, super mesh trawl net, rope trawl net, super plus trawl net and kite trawl net-have been widely used by large trawlers above 1,500gt in size since 1982. Regarding the fishing efficiency, the super plus trawl net and kite trawl net were acknowledged as higher than other nets. Maximum mesh size of super-plus trawl net and kite trawl net ranges about 20m, whereas the length of net about 150m, and high-tech polyethylene is used as the material of rope part. The problems involved in the North Pacific midwater trawl net may be summarized as follows ; (1) The dimension of fishing gear is too big compared with the towing power of trawler. (2) The mesh size of the rope part is too big compared with that of the common netting part. (3) The net is often torn out in the connecting position of the rope part and the netting part. (4) The net is not matched with the trawler and the otter board in many trawlers, so the shape of the trawl gear in the water is instable. (5) The fish school located near head rope, ground rope and side rope in the net recorder is not caught in practice because of the net instability.