• 한국정밀공학회지
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• 제16권6호
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• pp.123-132
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• 1999

This paper describes a research work of developing computer-aided design of lead frame, semiconductor, with blanking operation which is very precise for progressive working. Approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from pasticity theories, experimental results and the empirical knowledge of field experts. This system has been written in AutoLISP on the AutoCAD using a personal computer and in I-DEAS Drafting Programming Language on the I-DEAS Master Series Drafting with Workstation, HP9000/715(64). Transference of data between AutoCAD and I-DEAS Master Series Drafting is accomplished by DXF(drawing exchange format) and IGES(initial graphics exchange specification) methods. This system is composed of five modules, which are input and shape treatment, production feasibility check, strip-layout, data-conversion and die-layout modules. The process planning and Die design system is designed by considering several factors, such as complexities of blank geometry, punch profiles, and the availability of a press equipment and standard parts. This system provides its efficiecy for strip-layout, and die design for lead frame, semiconductor.

• 한국통신학회논문지
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• 제35권4C호
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• pp.329-336
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• 2010

분산 소스 부호화 시스템은 복호복잡도가 높다는 문제점을 갖는다. 본 논문에서는 신드롬 기반의 분산 소스 부호인 low-density parity check accumulate (LDPCA) 부호의 복호복잡도를 효율적으로 낮추기 위하여 LDPC 부호에 사용되는 각종 정지조건을 LDPCA 복호기에 적용하고 이에 따른 복잡도를 평가하였다. 대표적으로 convergence of mean magnitude (CMM) 정지 조건을 적용하여, 정지 조건을 사용하지 않았을 때보다 압축부호율 손실을 2% 이하로 발생시키며 약 85%의 복호복잡도 감소 효과를 얻을 수 있었다. 더불어 사용되는 부호의 성능을 파악하고 있을 때 초기에 과잉 신드롬을 전송하는 방법과, 채널 정보가 얻기 힘든 경우 기존 정지조건을 부호율 적응적인 LDPCA 부호에 적합하게 수정하는 방법을 제안하였다.

• 음성과학
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• 제14권2호
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• pp.35-42
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• 2007

The aim of this study is to analyze the correlation between current intensity and amplitude of stimulus artifact on the cochlear implantee, and to find out basic information to check the device failure. Subjects were a prelingual child and 3 postlingual adults with more than severe hearing losses. The charge-balanced biphasic pulses were presented at stimulus rates of 11 pulses per second, each pulse width of $25{\mu}s$ with monopolar mode(MP1+2). Current intensities were delivered at 27.5, 33.7, 41.3, 50.5, 61.9, $75.8{\mu}A$. Stimulus artifacts were recorded by evoked potential system. This procedure was performed just before the initial stimulation, and then, the amplitude of stimulus artifacts were compared with each current intensity. The amplitude of stimulus artifacts was increased significantly according to the current intensity (p<0.01). The results suggest that the change of the amplitude of stimulus artifact can be used as a good cue to check the device failure in the cochlear implantee.

• 대한장애인치과학회지
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• 제9권1호
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• pp.25-29
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• 2013

Most of disabled people face hardness in caring their general oral hygiene by themselves. So that, they are once involved in dental caries or periodontal disease, they have much bigger chance of aggressive progress. Therefore preventive dentistry is more important to disabled one than non-disabled. They need to be checked with routine periodic dental examination and by that, oral disease must be found at initial stage. We selected 37 patients from newly visited 237 patients who had dental treatment at the free dental clinic, Gangnam district, Seoul, between 2000 and 2001. This study is a comparative evaluation of first 2 years' treatment records of selected 37 patients (male 28, female 9) with that of their last 2 years. 24 of 37 have mental retardation, 9 have autistic disorder, 2 have auditory disorder, 1 has brain disorder and 1 has crippled disorder. Their dental treatment records categorized by 4 level; score 4 stands for endodontic treatment, score 3 stands for general conservative treatment, score 2 stands for preventive treatment, such as sealant and score 1 stands for routine check. In first 2 years of treatment, average score was 2.85 which score means approximately general conservative treatment. And that of last 2 years was 1.44, which means routine check. In early time of their visit, they will receive the treatment due to their chief complaint. And after that early time, they can have a routine check so that they can be treated before the disease get worse. The patient's oral health can remain decent only by a simple treatment.

• 한국통신학회논문지
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• 제35권9C호
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• pp.721-728
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• 2010

재귀적 구조의 SPCPC (single parity check product code)인 CAMC (constant amplitude multi-code) 는 반복적 복호를 행할 때 SPCPC에 비하여 오류 정정 성능이 우수하다. 본 논문에서는 대역확산 신호인 CAMC의 처리 이득이 성능 향상에 미치는 영향을 분석한다. 일반적인 곱 부호에서는 반복적 복호로 오류 정정 과정이 종료되지만, CAMC 는 반복적 복호 후의 역확산 과정에서 추가적으로 오류가 정정된다. 잔존하는 비트 오류의 수가 ($\sqrt{N}/2-1$)개 이하인 경우에는 (N은 코드워드의 길이), 역확산 과정에서 그 오류들은 모두 정정된다. 반복적 복호에서 EI (extrinsic information)의 분포 형태를 관찰한 결과, 초기의 EI 분포는 대체로 랜덤하나, 몇 회의 iteration 후에는 ($-E_{max}$) 혹은 ($+E_{max}$)의 이진 값으로 수렴한다. EI의 분포가 오류 정정의 진행 사항을 반영하는 점을 이용하는 iteration 제어 방법을 실험한 결과 Eb/No 에서 약 0.2 dB의 이득을 얻었다.

• 산업경영시스템학회지
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• 제29권4호
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• pp.8-17
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• 2006

Presented in this paper was to evaluate and improve the usability of a web-based logistics information system. The system was developed for the domestic company to track and monitor its own transportation vehicles and for the customers to check the current location of their packages by using Global Positioning System (GPS) and Short Massage Service (SMS). Since the initial system was developed under a tight schedule set by the company, the system designers and programmers did not focus on the usability of the system but on the functionality. Consequently, some usability problems of the system were discovered during the heuristic usability evaluation. This study was required to solve these usability issues. Usability problems of the initial system were identified and analyzed, and the user's requirements for the system were re-evaluated to meet the company's expectation. Several alternative designs were developed by fitted guidelines and then a updated system was developed. The updated system had an empirical usability test to find how much the initial system was improved from the heuristic evaluation. Two kinds of data were gathered during the tests: objective (completion time and number of errors) and subjects' preference. Data showed the updated system is better than the initial system in terms of usability. Presented in this paper includes introduction of the Usability evaluation, usability engineering process applied in this research, alternative design of GUI, usability test and results.

• 한국지반환경공학회 논문집
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• 제10권3호
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• pp.53-62
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• 2009

본 연구는 건설 현장에서 발생하는 비점오염원 발생 특성에 대해서 파악하고, 이에 대한 관리 기술들을 적용하여, 각 시설별 효과에 대해 평가하고자 하였다. 건설 현장의 공사 단계별로 비점오염원의 발생 특성을 보면, 공사 초반 즉, 토양 피복 상태가 교란되어 있는 경우, 강우 시 부유물질 부하량이 높게 나타나며, 강우 강도에 대한 민감도가 공사 후반에 비해 높은 것으로 확인되었다. 건설 현장에서 가설 형식으로 적용할 수 있는 기술로는 부유물질을 제어할 수 있는 Check dam, Silt fence 공법과 강우 시 토사 유실을 원천적으로 제어하는 Geotextile공법을 적용한 결과, Geotextile이 다른 공법에 비해 비점오염원 유출량 제어에 효과적인 것으로 확인 되었다. Check dam과 Silt fence는 공극에 의한 부유물질 제거 기능이 일부 있으나, 전반적으로 일시적 저류에 의한 침강효과로 오염물질을 제거 하는 특징이 있다. 이러한 가설 형식 처리 시설의 경우, 처리 효율이 낮아 주변 민원 또는 수계 오염을 유발할 수 있으며, 이에 부가적으로 가압식 여과 방법을 통해 연계 처리한 결과 만족할 만한 방류 수질을 기대할 수 있었다. 또한, 이러한 여과 방법은 여과 속도와 유입 부하량에 따라 처리 가능한 부하량이 결정되며, 효과적 운전을 위해서는 전처리가 반드시 필요하다.

• Journal of the Korean Wood Science and Technology
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• 제24권1호
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• pp.34-47
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• 1996

Veneers of two nominal thicknesses, 1.5 and 2.5mm, were rotary peeled from Japanese larch (Larix leptolepis). Dahurian larch (Larix gmelinei) and Radiata pine (Pinus radiata) bolts unheated and heated in the water vat temperature of $66^{\circ}C$ by rising a final temperature at 10cm core of $60^{\circ}C$ to remain core diameter of 11.4cm. 1.5 and 2.5mm thick veneer cut from the heated Japanese larch were significantly thinner than those of the unheated bolt and 2.5mm thick veneer cut from the heated Dahurian larch were significantly thicker than that of the unheated bolt. 1.5mm thick Dahurian larch veneer and 1.5 and 2.5mm thick Radiata pine veneers showed insignificant difference between the unheated and heated bolts, respectively. Check distance on the loose side of 1.5mm thick veneer cut from the heated Radiata pine was significantly wider than that of the unheated bolt. However check distances on the loose side of 1.5 and 2.5mm thick Japanese larch and Dahurian larch veneers and 2.5mm thick Radiata pine veneers showed insignificant difference between the unheated and heated bolts. Also the depth of check on the loose side of three species showed insignificantly difference between the unheated and heated bolts. Arithmatic mean deviation($R_a$) and maximum height($R_{max}$) of the profile on the loose side of dried veneer by preheating the bolt compared with unheated bolts were different among apecies and between veneer thickness. The preheating treatment slightly affected qualities of these thin veneers such as 1.5 and 2.5mm. The yield of 2.5mm thick veneer from the heated radiata pine was significantly higher than that of the unheated bolt. However the yield of 2.5mm thick veneer for other two species and 1.5mm thick veneer for three species showed insignificant difference between the unheated and heated bolts. The yield of 2.5mm thick veneer for three species were higher than those of 1.5mm thick veneer. The average yields of green veneer of Japanese larch. Dahurian larch and Radiata pine were 57.1, 55.1 and 54.0 percent, respectively. Variables such as initial MC. drying time and veneer thickness had strong effect for Japanese larch veneer, less effect for Radiata pine veneer and nuch less effect on final MC for Dahurian larch veneer in jet drying. Correlation between the current MC and the drying time of Dahurian larch with low variation of initial MC was higher than those of Japanese larch and Radiata pine veneer with high variation of initial MC in high temperature drying. Thickness shrinkages of 2.5mm thick veneer for Japanese larch and Radiata pine were higher than those of 1.5mm thick veneers, but shrinkages of Dahurian larch veneer were similar between two nominal veneer thicknesses.

• 대한수학회보
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• 제57권4호
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• pp.839-850
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• 2020

For functions f(z) = z + a₂z² + a₃z³ + ⋯ belonging to particular classes, this paper finds sharp bounds for the initial coefficients a₂, a₃, a₄, as well as the sharp estimate for the second order Hankel determinant H₂(2) = a₂a₄ - a₂³. Two classes are treated: first is the class consisting of f(z) = z + a₂z² + a₃z³ + ⋯ in the unit disk 𝔻 satisfying $$\|\(\frac{z}{f(z)}\)^{1+{\alpha}}\;f^{\prime}(z)-1\|<{\lambda},\;0<{\alpha}<1,\;0<{\lambda}{\leq}1.$$ The second class consists of Bazilevič functions f(z) = z+a₂z²+a₃z³+⋯ in 𝔻 satisfying $$Re\{\(\frac{f(z)}{z}\)^{{\alpha}-1}\;f^{\prime}(z)\}>0,\;{\alpha}>0.$$

• 한국해양공학회지
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• 제22권4호
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• pp.106-113
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• 2008

This paper presents an underwater navigation system based on range measurements from a known reference station fixed on the sea bottom or floated at surface with a buoy, for which the system is extended to 3-dimensional coordinates. We formulated a state equation in polar coordinates and constituted an extended Kalman filter for discrete-time implementation of the navigation algorithm. The autonomous underwater vehicle, lSiMl, cruising with a constant speed can estimate its trajectory using just range measurements and additional depth, heading and pitch sensors. Simulation studies were performed to evaluate the underwater navigation of the maneuvering AUV with range measurements. We modulated the sample rate of range measurements to evaluate the effect of the update rate, and changed the initial position error of the AUV to check the robustness to estimation errors. Simulation results illustrates that the extended navigation system provides convergence of the state estimates. The navigation system was conditionally stable when it had initial position errors.