• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.57
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• pp.21-39
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• 2000

BOM(Bill of Materials) is a listing or description of raw materials, parts, and assemblies that define a product. In manufacturing companies that produce various products with short life cycles, it is very important to manage the BOM of products with various options and versions efficiently. BOM information should be required to share among the departments of engineering, production control, material purchasing, cost management, and shop floor within a manufacturing company. In order to share BOM information efficiently, information system based on WWW(World Wide Web) should be developed. Thus, this paper models and implements Web-based Generic BOM Management System (WGBMS) for management of a number of variant products which are consisted of standard parts under ATO(Assemble To Order) production environment. Also, object-oriented methodology was used to model a generic BOM and phases of navigational design and interface design were introduced to implement the prototype of WGBMS. And Object-Relational Database Management System (ORDBMS) was used to construct the WGBMS database.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.8
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• pp.706-712
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• 2012

This paper presents a sensor network and operation for multiple autonomous navigation platform and transport service. Multiple platform navigate with inside sensors and outside sensors while acquiring and process some useful information. Each platform communicates each other by navigational information through central main server. Efficient sensor network systems are considered for the scenario which some passengers call the service and the vehicle accomplish its transport service by transporting each caller to the destination by autonomous manners. In the scenario, all vehicles perform a role of sensor system to the central server and the server handles each information and integrate with faster procedure in the wireless 3G network.

• Journal of information and communication convergence engineering
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• v.17 no.4
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• pp.227-233
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• 2019

In long-haul optical communication system consisting of standard single-mode fiber spans and fiber amplifiers, such as the erbium-doped fiber amplifier, performance is deteriorated by signal distortion due to chromatic dispersion and nonlinearity of the fiber. A combination of dispersion management and optical phase conjugation is an effective technique to compensate for the distortion. In an optical link configured by this combination, a dispersion map mainly affects the compensation of the distorted optical signals. This paper proposes new dispersion maps configured by the decaying or expanding distribution of residual dispersion per span (RDPS) in a dispersion-managed link combined with a midway optical phase conjugator. The effect of the proposed dispersion maps on the compensation for distorted 24 channel × 40 Gbps wavelength-division multiplexed signals was assessed through numerical simulation. It was confirmed that all the proposed dispersion maps are most appropriate for the compensation and, furthermore, for the flexibility of link configuration than conventional links.

• Journal of information and communication convergence engineering
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• v.16 no.2
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• pp.67-71
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• 2018

The various techniques to compensate for the signal distortion due to the group velocity dispersion (GVD) and nonlinear Kerr effects of optical fibers in the optical links have been proposed in the literature. We propose a flexible dispersion-managed link configuration consisted of single-mode and dispersion-compensating fibers with irregular dispersion coefficients over all fiber spans, and an optical phase conjugator added midway along the optical links. By distributing the lengths of the single mode fibers, we achieve a flexible optical link. The simultaneous ascending and descending distribution of the single-mode fiber lengths before and after the optical phase conjugator, respectively, best compensates the distorted wavelength division multiplexed signals in the optical link with non-fixed coefficients. Our result is consistent with those of our previous work on fixed coefficients. Therefore, to improve the compensation at any magnitude of dispersion coefficient, we must artificially distribute the lengths of the single-mode fibers into a dispersion-managed link.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.195-196
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• 2016

In the maritime mobile radiocommunication service, AIS(Automatic Identification System) devices are most widely using for the exchange of ship's navigational information. The AIS time slot usage increases due to increasing number of ships installed with AIS, and thus the reception rate of AIS data decrease. In order to mitigate this problem, international organizations recommend a sectorised receiving technique using directional antenna. This paper analyzed the sectorised receiving effectiveness of AIS data using Yaga antenna.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1956-1959
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• 2021

AIS(Automatic Identification System) provides navigational information including identification, position, a ship's course and status to ground and other vessels. To obtain AIS Marine Equipment Approval Service, various requirements are required and meet the requirements International Standards. However, most of the requirements are to identify essential functions, response time, hardware requirements, and communication protocols of AIS. The requirements for the quality of SW are not sufficient or detailed, and the weight is relatively low. As role of SW grows and types become more diverse, AIS SW quality inspection is essential. In this paper, We apply eight-quality characteristics of ISO/IEC 25023 standard to improve SW coverage quality of AIS. Suggest additional AIS SW requirements based on the eight quality characteristics of ISO/IEC 25023 standard.

• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.199-204
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• 2021

We propose a dispersion-managed link with a non-midway optical phase conjugator (OPC), in which the residual dispersion per span (RDPS) of each fiber span is different for each transmission section before and after OPC. We numerically demonstrate the compensation for 960-Gb/s wavelength-division multiplexed (WDM) signals distorted by chromatic dispersion and Kerr nonlinearity of the fiber. We consider different cases for non-midway OPC, including six fiber spans - OPC - 14 fiber spans and 14 fiber spans - OPC - 6 fiber spans. The numerical results show that the compensation of the distorted 960 Gb/s WDM is more efficient when the OPC is placed after 6-th fiber span as compared to after the 14-th fiber span. Our simulation results also indicate that the compensation effect increases when the difference in net residual dispersion between both transmission sections is not large, but they are not the same. Under this condition, the larger the magnitude of the RDPSs of each fiber span, the greater the compensation.

• Journal of information and communication convergence engineering
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• v.20 no.4
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• pp.235-241
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• 2022

A dispersion map was proposed to improve the compensation effect of a distorted WDM (wavelength division multiplexed) channel in a dispersion-managed link coupled with optical phase conjugation. The dispersion map is an origin-symmetric structure around the optical phase conjugator in the middle of the transmission path. In addition, the dispersion map has a form in which a constant dispersion accumulation pattern is repeated regularly. Through simulation, we confirmed that the application of the origin-symmetric dispersion map with a repetitively shaped configuration was more effective in compensating for the distorted WDM channel than in the dispersion-managed link with a conventional dispersion map. In addition, we confirmed that the compensation effect could be increased when the cumulative dispersion distribution of the origin-symmetric distribution map had a positive value in the first half section and a negative value in the second half section. Further, we observed that as the number of repeated dispersion accumulation patterns increased, the residual dispersion per span should also be increased.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.4
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• pp.381-388
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• 2015

Global Maritime Distress and Safety System (GMDSS) equipment and Electronic Chart Display & Information System (ECDIS) are typical equipment which help seafarers to obtain information for ship's safe navigation. In this study, a survey on using of GMDSS equipment and ECDIS was conducted on a total of 260 ship masters and crew who have been working on ocean-going vessels. The subjects were asked about the usage, and level and reason of satisfaction or dissatisfaction of GMDSS equipment and ECDIS, the leading navigational system from which they receive information. The survey showed that the third- and fourth-most frequently used equipment, MF/HF and INMARSAT (telex), were deemed to be the second- and third-most useless equipment. It means that the frequency of device usage is not proportionate to the level of navigational safety. Especially, 'ease of device use (42.3%)' and 'necessity of the provided information (50%)' were highlighted as factors increasing the level of satisfaction with the system. The survey result shows that ship safety cannot be realized by only adopting advanced systems, technology and services. It emphasizes the need to consider the level of 'accessibility and appropriateness of the information' and 'ease of device use'. Discussions implemented by the IMO on various policies and regulations are aimed at securing ship safety. In order to achieve the goal, such institutions should be validated by end-users and relevant studies should be conducted.

• Journal of Navigation and Port Research
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• v.30 no.1 s.107
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• pp.9-15
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• 2006

At the adjacent sea area of Busan Central Wharf, a variety of vessels, such as middle-large passenger ships, small hugh speed crafts, container ships, cargo ships and working boats as well as small miscellaneous vessels are freely sailing comparatively without special rules and marine traffic control. In this research, we analyzed traffic stream and navigational characteristics cf main traffic route based on statistics and distribution of tracks by ship's type and tonnage cf the passing vessels after conducting marine traffic survey twice using exclusive software. We examined the traffic safety of the passing vessels by classifying the sea area by each function based on the analysis about this traffic situation, and analyzing the effect by designating 'Inner passage'. We also studied the plan for the effective rearrangement cf Central Wharf considering basically the traffic safety of arrival and departure in a point of view of navigators.