간행물
Journal of Korean Navigation and Port Reserch KCI 등재 한국항해항만학회지
- 발행기관 한국항해항만학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1598-5725 (Print)2093-8470 (Online)
- 수록기간 1977 ~ 2020
- 주제분류 농수해양 > 해상운송학 농수해양 분류의 다른 간행물
- 십진분류KDC 559DDC 629
권호리스트/논문검색
Vol.22 No.4 (1998년 12월) 8건
1.
1998.12
서비스 종료(열람 제한)
There are three basic modes of operation of ships: liner, tramp and industrial operations. Industrial operations, where the owner of the cargo, i.e. the industrial carrier controls the ships, abound in the shipment of bulk commodities, such as oil, chemicals and ores. Industrial carriers strive to minimize the shipping cost of their cargoes. This paper is concerned with the operational optimization problem of a fleet owned by major international oil company. The major oil company is a holding corporation for a group of oil producing, transporting, refining, and marketing companies located in various countries throughout the world. The operational optimization problem of the fleet is divided into two-phases. The front end corresponds to the optimization of transporting crude oil, product mix, and the distribution of product oil to meet market demand. The back end tackles the operational optimization problem of the fleet to meet the transportation demand derived from the front end. A case study is carried out with the H major oil company problem composed by reflecting the practices of an international major oil company. The results are summarized and examined in the point of optimization for the total operation of the H major oil company and the operational optimization problem of the fleet. The paper concludes with the remark that the results of the study might be useful and applicable in practices of these related decision problems.
2.
1998.12
서비스 종료(열람 제한)
The marine self-organizing VHF data link is a digital radio link with self-organizing ability, which exploits the STDMA algorithm and operates in marine VHF channels. It can support the applications of surveillance, situation awareness and communication. It is the core technology of the Universal AIS which is considered as a future surveillance system at sea by the IMO. In this paper, the operational principle of the marine self-organizing VHF data link is introduced. Simultaneously, a new access protocol is proposed to enhance the marine self-organizing VHF data link so as to support point-to-point communication. The point-to-point communication is one of the most important bases to establish dynamic internetworks among computers on the bridges in the future.
3.
1998.12
서비스 종료(열람 제한)
The whistle is a very important information source for the safety navigation under foggy weather. But navigator has no concern about this, because it must be achived by human hearing sense and considered as a vague signal. If the range and relative bearing of signal source can be detected automatically, it would be very useful system for preventing marine casualties making a lot of economic loss and environment pollution. Before the algorithm of 2-dimensional sound source tracking system was reported. This paper describes the method that can obtain the time lag between three signals and the theory of cross-correlation analysis and subtraction method for cauculating the time lag by using the digital signal data sequences. And a series of experiments were carried out for various position of sound source in the range from 200cm to 530cm. As a result, we have recognized that sound source tracking system is possible to the sea field with improvement of position error.
4.
1998.12
서비스 종료(열람 제한)
This paper presents a procedure for automated extraction of ridge shadows in noisy gray images. This procedure mainly consists of 1) a deformable model which is designed basing upon the knowledge about the shape of shadows and is expected to be useful in extracting ridge shadows especially located in low signal to noise ratio background, and 2) the scale space scheme which is also useful even if there is less information about the size and the positions of ridge shadows in advance. This procedure is applied to artificial images and its performance is evaluated experimentally.
5.
1998.12
서비스 종료(열람 제한)
A recently constructed commercial ship is a complexive integrated system like a small city in which has a generator, power distributing facilities, various radio equipments and high power circuit breakers are installed. Therfore it could make a malfunction of the microprocessor in the various control units which are so important during the ocean voyage of larger ship. This paper has studied whether is properly required or not on the view of the actual electro magnetic compatibility status on the electromagnetic interference and suceptibility test requirments listed on the IACS (International Association of the Classification Society). Through these results, we are looking forward to the new suggestions of the Electro Magnetic Compatibility test in order to reduce the malfunction in the ship regarding test item, test level, and test condition.
6.
1998.12
서비스 종료(열람 제한)
A Design of Ferrite Electromagnetic Wave Absorber Three Layered Type with Wide-Band Characteristics.
According to the rapid development of the electric industry, the demand of the frequency allocation and the usage of electromagnetic wave are increased due to automation of modem society. Electromagnetic wave absorbers for anechoic chamber are needed to broaden the effective frequency bandwidth, reduce the thickness, and decrease the weight. There are various absorbers proposed for the above conditions, but they could not decisively solve the above requirements. The Electromagnetic wave absorber made by a conventional ferrite tile has, for example, broadened the effective frequency bandwidth by the way of forming air layer(practically in urethane foam, etc.) on the ferrite tile. Therefore, an air layer is formed between a reflection plate and a sintered Ni-Zn ferrite tile of 7 mm in thickness, which has reflectivity less than -20 dB from 30 MHz to 400 MHz in bandwidth. In this paper, a broadband electromagnetic wave absorber are designed, which has the reflection characteristics less than -20 dB from 30 MHz to 8,000 MHz in the bandwidth. A super broadband electromagnetic wave absorber is achieved by inserting square Ferrite Cylinders Type with the thickness less than 23.5 mm and with the frequency band from 30 MHz to 8,000 MHz under the above tolerance limits. The purpose of this research is on the development of a universal anechoic chamber for measuring radiated electromagnetic wave or immunity of electronic equipments, GTEM-cell and also a wall material for preventing TV ghost, etc.
7.
1998.12
서비스 종료(열람 제한)
A quick and automatic detection with no harm to the goods is very important task for improving quality control, process control and labour reduction. In real fields of industry, defect detection is mostly accomplished by skillful workers. A narrow band eliminating spatial filter having characteristics of removing the specified spatial frequency is developed by the author, and it is proved that the filter has an excellent ability for on-line and real time detection of surface defect. By the way,. this spatial filter shows a ripple phenominum in filtering characteristics. So, it is necessary to remove the ripple component for the improvement of filter gain, moreover efficiency of defect detection. The spatial filtering method has a remarkable feature which means that it is able to set up weighting function for its own sake, and which can to obtain the best signal relating to the purpose of the measurement. Hence, having an eye on such feature, theoretical analysis is carried out at first for optimal design of narrow band eliminating spatial filter, and secondly, on the basis of above results spatial filter is manufactured, and finally advanced effectiveness of spatial filter is evaluated experimentally.
8.
1998.12
서비스 종료(열람 제한)
The super wideband electromagnetic wave absorber in RF-A-PF type has been proposed, which can be used for an anechoic chamber, wall material to prevent TV ghost, etc, In this paper, Nix-Mg0.1-Zn(1-x-0.1)·Fe2O4 Ferrite Powder has been fabricated. Using this, then, [Nix-Mg0.1-Zn(1-x-0.1)·Fe2O4-Rubber composite for RF-layer in the RF-A-PF type absorber has been fabricated and its characteristics has been analyzed. As a result, it has been shown that the Nix-Mg0.1-Zn(1-x-0.1)·Fe2O4-Rubber composit with the quantity x of Nix between 0.5 and 0.6 is suitable for the RF-layer in the case of which the grain size is sub-micrometer order.
