• 대한기계학회논문집A
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• 제29권3호
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• pp.447-454
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• 2005

This paper presents a new paradigm for 3-axis tool path generation based on an incomplete 2-manifold mesh model, namely, an inexact polyhedron. When geometric data is transferred from one system to another system and tessellated for tool path generation, the model does not have any topological data between meshes and facets. In contrast to the existing polyhedral machining approach, the proposed method generates tool paths from an incomplete 2-manifold mesh model. In order to generate gouge-free tool paths, CL-meshes are generated by offsetting boundary edges, boundary vertices, and facets. The CL-meshes are sliced by machining planes and the calculated intersections are sorted, trimmed, and linked. The grid method is used to reduce the computing time when range searching problems arise. The method is fully implemented and verified by machining an incomplete 2-manifold mesh model.

• 한국가시화정보학회지
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• 제3권1호
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• pp.26-35
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• 2005

The combination of ultrasound echo images with digital particle image velocimetry (DPIV) method has resulted in a two-dimensional, two-component velocity field measurement technique appropriate for opaque flow conditions including blood flow in clinical applications. Advanced PIV processing algorithms including an iterative scheme and window of offsetting were used to increase spatial resolution. The optimum concentration of the ultrasound contrast agent used for seeding was explored. Velocity validation tests in fully developed laminar pipe flow and pulsatile flow showed good agreement with both optical PIV measurements and the known analytic solution. These studies indicate that echo PIV is a promising technique for the non-invasive measurement of velocity profiles and shear stress.

• 제어로봇시스템학회논문지
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• 제16권2호
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• pp.145-150
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• 2010

This paper deals with reduction of torque ripple in a brushless DC motor with input voltage control. The commutation torque ripple can be controlled with varying input voltage, but cogging torque is independent on it. So, in this paper a strategy for minimizing torque ripple is proposed by offsetting the cogging torque with deliberate voltage control. The optimal condition is determined with variable voltage levels and advance angles. As results, it is shown that the method causes 63% decrease of torque ripple.

• 한국정밀공학회지
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• 제25권3호
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• pp.157-164
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• 2008

While developing physical prototype from CAD model, rapid prototyping mainly focuses on two key points reducing time and material consumption. So, we have to change from a traditional solid model to building a hollowed prototype. In this paper, a new method is presented to hollow out solid objects with uniform wall thickness to increase RP efficiency. To achieve uniform wall thickness, it is necessary to generate internal contour by slicing the offset model of an STL model. Due to many difficulties in this method, this paper proposes a new algorithm that computes internal contours computing offset model which is generated from external contour using wall thickness. Proposed method can easily compute the internal contour by slicing the offset surface defined by the sum of circle swept volumes of external contours without actual offset and the circle wept volumes. Internal contour existences are confirmed by using the external point. Presented algorithm uses the 2D geometric algorithm allowing RP implementation more efficient. Various examples have been tested with implementation of the algorithm, and some examples are presented for illustration.

• 한국컴퓨터정보학회논문지
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• 제16권8호
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• pp.19-27
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• 2011

과거 접근제어에 대한 연구는 효율적인 측면보다 안전성에 더 많은 초점이 맞추어져 있었다. 본 연구는 배터리나 메모리 등의 자원이 제약적인 개인 휴대용 단말기와 같은 환경에서 XML 데이터 스트림의 효율적이고 안전한 질의처리에 대한 방법을 제안한다. 특히, 본 연구는 접근제어 처리과정에서 발생할 수 있는 추가적인 오버헤드를 각 질의처리 단계별로 찾아내고 최소화하여, 자원의 사용을 최적화하며 안전한 결과를 얻기 위한 최소한의 오버헤드를 갖는 접근제어 처리 방법을 제안한다. 끝으로, 실험을 통해 본 연구에서의 제안방법에 대한 우수성 분석을 하였다.

• 의료법학
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• 제23권2호
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• pp.171-209
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• 2022

2021년에도 의료와 관련된 많은 판결들이 있었는데, 그 중 본 논문에서 검토한 판결들은 다음과 같다. 먼저 진료기록 부실기재 및 변조 등과 주의의무위반 관련 판결은 의료과실 유무 등에 관한 일차적 판단자료인 진료기록이 사후에 수정된 사례에 관한 것으로 그 수정내용 및 수정시기에 비추어 사후에 수정된 진료기록 내용은 고려하지 않고 최초 작성된 진료기록을 토대로 과실 유무 판단을 하였다. 다음으로 비만치료약 처방 등에 대한 손해배상책임을 묻는 사례에 관한 판결은 처방과 관련한 과실을 인정하였으나 상당인과관계를 부정하여 재산상 손해배상책임을 부정하고, 설명의무위반에 따른 위자료만 인정하였다. 또한, 환자의 가해자에 대한 기왕치료비 손해배상채권을 대위하는 국민건강보험공단의 대위범위에 관한 전원합의체판결은 '과실상계 후 공제방식'을 취해온 기존 판례를 변경하여 '공제 후 과실상계방식'으로 대위 범위를 판단하여 피해자 보호를 도모하였다. 그리고 과실 유무에 관해 진료기록감정회신결과와 달리 판단한 판결은 과실유무 판단을 함에 있어 진료기록감정결과에 구속되는 것은 아니고 자유심증에 따라 판단한다는 입장에 따라 규범적으로 판단하였다. 마지막으로 국민건강보험공단의 요양급여비용환수처분과 관련해서는 비의료인이 개설한 의료기관에 대한 환수처분을 함에 있어서도 재량권을 행사해야 한다는 판결과 시설 및 인력을 공동이용한 의료기관에 대한 환수처분의 경우 그 환수범위를 세부적으로 판단해야 한다는 판결을 검토하였다.

• Journal of Computational Design and Engineering
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• 제2권1호
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• pp.55-66
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• 2015

To satisfy safety regulations of Economic Commission for Europe (ECE), the surface regions of automobile parts must have a sufficient degree of roundness if there is any chance that they could contact a sphere of 50.0 mm radius (exterior parts) or 82.5 mm radius (interior parts). In this paper, a new offset-based method is developed to automatically detect the possible sphere-contacting shape of such parts. A polyhedral model that precisely approximates the part shape is given as input, and the offset shape of the model is obtained as the Boolean union of the expanded shapes of all surface triangles. We adopt a triple-dexel representation of the 3D model to enable stable and precise Boolean union computations. To accelerate the dexel operations in these Boolean computations, a new parallel processing method with a pseudo-list structure and axis-aligned bounding box is developed. The possible sphere-contacting shape of the part surface is then extracted from the offset shape as a set of points or a set of polygons.

• 전기학회논문지
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• 제61권11호
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• pp.1700-1705
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• 2012

This study is focusing on ripple elimination in the band pass filter. There are generally two design methods in IIR filter design, which are a direct method and an indirect one. The indirect design method that designs the digital IIR LPF using the prototype analog LPF is applied to this study. A Butterworth filter and a Chebyshev filter are the typical prototype analog LPFs. This study shows characteristics of the digital IIR LPFs that are transformed from the prototype analog LPFs. The designed Butterworth and Chebyshev IIR LPFs are also designed as the band pass filters by frequency transformation in order to compare with the proposed cascading Chebyshev BPFs. This study shows frequency characteristics between the transformed IIR BPFs and the proposed cascading Chebyshev BPFs as well. The proposed cascading Chebyshev BPF is designed by cascading the different orders of Chebyshev BPFs. The aspect of the cascading filter is offsetting the ripples to descend them while the pass band ripples of the Chebyshev filter are ascending and vice versa. The designed cascading Chebyshev filter shows the flatness and the sharpness, which represent the advantages of Butterworth filter in the pass band and of Chebyshev filter in the transition band respectively. This result verifies the validity of the designed filter.

• 한국기계가공학회지
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• 제2권2호
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• pp.52-59
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• 2003

Cam mechanism is a machine part frequently used in machinery. Specially, conjugate cam mechanism is very suitable for the high speed working and the heavy power translation. Then a conjugate cam mechanism need high precision for the relations between cam profiles and follower rollers. So, its design and manufacturing are very difficult. Thus, this study is a branch of exclusive CAM systems for design and NC machining of conjugate earn mechanism based on a master plate earn profile in order to exchange an old plate cam mechanism to a new conjugate earn mechanism. For the design of the other cam profile by using a master cam profile, some calculation processes were used by vector summation methods, from master cam profile data to the center data of master follower, from the center data of master follower to the center data of the other follower considered in link mechanism, and offsetting in the center direction of base circle of the other cam from the center data of the other follower. Finally, a sample conjugate cam was selected and machined m order to prove the contents of this study.

• Journal of Power Electronics
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• 제13권3호
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• pp.349-361
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• 2013

As a result of the advantages such as high efficiency, continuous current and high stability margin, push-pull converter with continuous current (PPCWCC) is competitive for battery discharge regulator (BDR) which plays an important role in power conditioning unit (PCU). Leakage inductance yields current spike in low-ripple current of PPCWCCs. The operating modes are added due to leakage inductance. Therefore the steady state performance is affected, which is embodied in the spike of low-ripple current. PPCWCCs which are suitable for BDR can be separated into three types by current spike characteristics. Three representative topologies IIs1, IIcb2 and Is3 are analyzed in order to investigate the factors on the magnitude and duration of spike. Equivalent current sampling method (ECSM) which eliminates the sampling time delay and achieves excellent dynamic performance is adopted to prevent the spike disturbance on current sampling. However, ECSM reduces the sampling accuracy and telemetry accuracy due to neglecting the spike. In this paper, ECSM used in PPCWCCs is summarized. The current sampling error is analyzed in quality and quantity, which provides the foundation for offsetting and enhancing the telemetry accuracy. Finally, current sampling error rate of three topologies is compared by experiment results, which verify the theoretical analysis.