• The Korean Journal of Zoology
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• v.8 no.2
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• pp.19-22
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• 1965

Scaptomyza 속의 1 신종, drosophila 속의 2 신종의 기재와 Amiota 속의 한국미기록2 종을 기록했다. Scaptomyza(Scaptomyza) choi.sp.nov. 제주 -각씨 초파리(신칭) , Drosophila (Hirtodrosophila) nigripennis sp. nov. 검은톱니-초파리(신칭), Drosophila (Hirtodrosophila) pseudonokogiri sp.nov. 헛톱니-초파리(신칭) Amiota (Amiota) stylopyga WAKAHAMA& OKADA ， 1958 Amiota (Amiota) dispina OKADA, 1960.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.315-331
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• 2008

A total of 12 species in six genera of the poneromorph subfamilies group in Korea was reviewed. All investigated specimens are classified into three subfamilies; Amblyoponinae, Proceratinae and Ponerinae. Totally six genera were known and Cryptopone, Hypoponera, Pachycondyla and Ponera belong to the subfamily Ponerinae and Amblyopone and Proceratium belongs to the subfamily Amblyoponinae and Proceratinae respectively. In this study, keys to the all known genera and species of the subfamilies in Korea are presented. A synonymic list, description of a worker and comments on each species are given with SEM photographs of worker.

• The Journal of the Korea Contents Association
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• v.8 no.7
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• pp.53-57
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• 2008

The discretized saw-tooth map with the 16-bit finite precision which is one of the 1-dimensional chaotic maps is designed, and the circuit of chaotic binary sequence generator using the discretized saw-tooth map is presented also in this brief. The real implementation of designed chaotic map is accomplished by connecting the input and output lines exactly according to the simplified Boolean functions of output variables obtained from truth table which is discretized. The random binary output sequences generated by mLFSR generator were used for the inputs of descretized saw-tooth map, and, by the descretized map, chaotic binary sequence which has more long period of 16 times minimally is generated as a results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.13-19
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• 2016

The flow-excited Helmholtz resonance phenomenon was investigated numerically using Reynolds averaged Navier-Stokes approach. The fundamental cause of the Helmholtz resonance phenomenon is known as shedding of a single discrete vortex from orifice edge that travels during one period of the oscillation. In this study, serrated deflector, which is biomimetic design of the owl's feather, is used to split a single vortex into small vortices. Rectangular deflector and serrated deflector are compared with numerical results of pressure and streamline inside the cavity. Consequently, the serration breaks the shedding period of vortex core and eliminates the resonance. Also, it changes the flow pattern in according to the location of different serration height. By making inflows and outflows occur simultaneously in spanwise direction in the cavity, the period of Helmholtz resonance disappears. Comparing between rectangular deflector and serrated deflector, the serrated deflector can deal with the Helmholtz resonance more effectively.

• Journal of Sensor Science and Technology
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• v.7 no.4
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• pp.225-233
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• 1998

The principle, design, and application of a gear-tooth sensor for the rough environmental conditions such as high temperatures of up to $150^{\circ}C$ are studied. The rotation of a tooth wheel is detected by a couple of Hall elements manufactured on the SIMOX wafer by a methode of differential detection using bipolar silicon technology. The product sensitivity of the Hall element is about 510 V/AT over a wide temperature range of $-40^{\circ}C{\sim}150^{\circ}C$. The differential Hall sensor makes the maximum possible distance between sensor and tooth wheel wider than that when single Hall element is used over a wide temperature range, and the maximum detectable distance is 4.5mm at driving current of 4mA.

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.125.4-125
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• 2003

• Proceedings of the Korean Fiber Society Conference
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• 2000.04a
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• pp.185-188
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• 2000

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.37-47
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• 1998

This study discusses the feed dog feeding mechanism of an industrial lock stitch sewing machine, which is a good example to study a machine kinematics. The feed dog feeding mechanism makes the fabrics directly be fed by an elliptic motion of the feed dog that is moved by a rotation of the top shaft and controlled by the feeding control mechanism. This study makes mathematical expressions of machine's motion in the feed dog feeding mechanism. Thus, the motions of this mechanism are characterized, namely how an elliptic motion of the feed dog is affected by the feeding control mechanism. Therefore, the above mathematical expressions may be a basis for the new design of the feed dog feeding mechanism and may be adapted to analysis. Development of the similar feed dog feeding mechanism can be applied to other type sewing machine.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1546-1552
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• 1993

We proposed an adaptive block truncation coding(BTC) using gradient and a new initial value. We used gradient of sobel operator as a new category classification coefficient to reduce Jagged appearance at edge part. We defined a new initial value to reduce large quantization error in the 4-level quantizer block including edge part. By computer simulations, we showed that the proposed method less computation load, reduced jagged appearance at edge part, also improved PSNR more than the conventional adaptive BTC.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.191-197
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• 1995

Faunistic survey of ant was carried out twice in April and July 1994 from Is. Sohuksando located in westsouthern area in Korea. Thirty-seven species were identified ut of Five hundred and thirty seven colonies collected. Among them, Camponotus nawai Ito and Smthistruma incerta Brown are found to be the first record from Korea.