• Journal of Korean Electronics
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• v.4 no.4
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• pp.130-132
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• 1984

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.2
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• pp.1-7
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• 1978

In this paper, a preliminary structural analysis of the information source of HANGEUL is performed statistically. And the results of the analysis are utilized to a KS HAHGEUL code, improving its transmission rate of 14%, on the basis of probability rankings of the fundamental HANGEUL elements. Forthermore Some problems about KS code, a coding method for the HAHGEUL information processing, as well as data entry are realized.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.1
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• pp.25-30
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• 1972

Data Communication by sending pulse train and verifying the lock-in of a phase locked loop in receiving end is studied. The noise rejection property inherent to PLL is analysed. By using about six pulses in a train, data transimission rate of 20k bit/sec. in a telephone cable is achieved, thus permitting high speed data communication and an exellent immunity against noise.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.3
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• pp.395-408
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• 1987

Turbulent flows in an axisymmetric reciprocating engine are numerically simulated at it's suction and compression stage. Amounts of heat transfer through the wall of the cylinder are also estimated. k-.epsilon. turbulence model is adopted and the law of the wall is applied at grid-points near the wall. More than 40 * 40 grids are reguried to reasonably predict flows and the 3-level finite difference scheme for the time derivative term appears to be effective rather than the 2-level scheme. Calculated mean velocity distributions shows good agreements with an available experimental data. The program reasonably simulates flow patterns and pressures throughout the suction and the compression stages of the reciprocating engine. Predicted intensities of turbulence are still deviated from measured data. Further researches for turbulence modeling are expected.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.2
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• pp.40-51
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• 1991

A Propeller design method using the newly developed blade section(KH18), which behaves better cavitation characteristics, is presented. Experimental results for two-dimensional foil sections show that the lift-drag curve and the cavitation-free bucket diagram of the new blade section are wider comparing to those of the existion NACA sections. This characteristic of the new section is particularly important for marine propeller applications since angle of attack variation of the propeller blade operating behind a non-uniform ship's wake is relatively large. A lifting surface theory is used for the design of a propeller with the developed section for a 2700 TEU container ship. Since the most suitable chordwise loading shape is not known a priori, chordwise loading shape is chosen as a design parameter. Five propellers with different chordwise loading shapes and different foil sections are designed and tested in the towing tank and cavitation tunnel at KRISO. It is observed by a series of extensive model tsets that the propeller(KP197) having the chordwise loading shape, which has less leading edge loading at the inner radii and more leading edge loading at the outer radii of 0.7 radius, has higher propulsive efficiency and better cavitation characteristics. The KP197 propeller shows 1% higher efficiency, 30% cavitation volume reduction and 9% reduction of fluctuating pressure level comparing to the propeller with an NACA section. More appreciable efficiency gain for the new blade section propeller would be expected by reduction of expanded blade area considering the better cavitation characteristics of the new blade section.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.1
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• pp.29-37
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• 1989

This paper presents an application of the extended DP matching method to the on-line recognition of cursive Hangeul (Korean characters). We decrease the number of matching's objects by performing rough classification matching which makes the best use of features in the first and the last segment of Hangeul. By adding the extraction function of the basic character patterns to DP matching method, we try to calculate precisely the difference among Hangeul. The extraction of the basic character patterns is done by examining the features of segments in character. Applying the extended DP matching method to the on-line recognition of cursive Hangeul, absorption of writing motion and stable separation of strokes can be performed with flexibility.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.8-15
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• 1985

This paper describes the design of Korean electronic Mail system which is installed at DECnet in Seoul National University computer center. In our system we introduce facilities for command processing and naming service in Korean, which was impossible in most mail systems. We emphasize flexibility in the design of Message Transfer Agent, for there are numer-ous code representions for Korean language.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.1
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• pp.1-8
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• 1979

This paper describes a simple asynchronous time dime division multiplexing system developed by means of a synchronous delta modulation. In realizing asynchronous multlplexlng system time author deals with a technique of multiplexing communication channels by reversing the polarity of output pulse and superimposing the channels at a certain time Interval. The results of experiments on the number of error pulses, signal-to-noise ratio and frequency characteristics have shown fair agreements with the theoretically predicted ones related to the system.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.1 no.1
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• pp.19-22
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• 1983

A contex-freegammar is defined over the Korean Alphabet which produces linear stings conforming to the sound structure of the language. Methods are then given for transforming these strings into a context-dependent syllabified two dimensional form Also the practical problems in developing d Korean line printer and suggestions for further research are presented.

• Journal of Navigation and Port Research
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• v.32 no.1
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• pp.9-14
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• 2008

VOF method is known as one of the most effective numerical techniques handling two-fluid domains of different density simultaneously. Present study deals with the numerical analysis of flow field around bodies steadily moving near free-surface using FLUENT-VOF method. Validations were made by applying to three typical examples ; 2-D submerged hydrofoil, 3-D surface piercing body and container ship. It was found that the commercial software, FLUENT, is useful in practical use, and VOF method is capable of handling free-surface around moving bodies although discussions are limited to the analysis in qualitative sense.