• Journal of the Korean Magnetics Society
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• v.24 no.5
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• pp.152-159
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• 2014

Magnetic gear can transmit torque without any mechanical contact among rotational parts in rotating mechanical systems. Especially, magnetic gear using rare-earth PMs can be used in variety of industry application because of their great power efficiency. Thus, recent trend shows that magnetic gear can be replaced with common mechanical gear. This paper deals with comparison and torque analysis for magnetic gears with parallel and Halbach magnetization according to various design parameters. Using a two dimensional (2D) finite element (FE) analysis, suitable gear ratio is selected. We performed analysis for magnetically connected inner and outer torque with respect to various design parameters including thickness of inner and outer PM, steel pole angle, segments of Halbach array and magnetization pattern of inner and outer PMs. Finally, we can obtain improved design model having parallel and Halbach magnetization with larger torque, compared with an initial design model.

• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.579-585
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• 2016

3D laser scanning can be used for scanning the freeform surface and building a model from which the measurements could be taken, in order to solve the difficulty with getting access to the exact freeform shape and position data of the complex building envelope. The shape making process using 3D scanning is as follows: point cloud, mesh surface segmentation, NURBS(Non-Uniform Rational B-spline) surface generation, and parametric solid model generation. In this research, we review previous studies, reverse engineering notion, importance of reverse engineering usage for freeform envelope, and previous cases in order to identify the detail reverse engineering process for prefabrication and construction of freeform panels using 3D laser scanning technology. Therefore, the purpose of this research is to present a basic information which should be considered during design and construction phase and improve quality and constructibility of freeform building by analyzing the reverse engineering process and case study for prefabrication and construction of freeform panels using 3D laser scanning. The research results will enable 3D shape engineering and design parameterization using reverse engineering to be used in various construction projects.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.64-71
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• 2010

Recently, to achieve high performance of the processor, the cache is splits physically into two parts, one for instruction and one for data. This paper proposes an architecture of asynchronous instruction cache based on mixed-delay model that are DI(delay-insensitive) model for cache hit and Bundled delay model for cache miss. We synthesized the instruction cache at gate-level and constructed a test platform with 32-bit embedded processor EISC to evaluate performance. The cache communicates with the main memory and CPU using 4-phase hand-shake protocol. It has a 8-KB, 4-way set associative memory that employs Pseudo-LRU replacement algorithm. As the results, the designed cache shows 99% cache hit ratio and reduced latency to 68% tested on the platform with MI bench mark programs.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1567-1572
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• 2012

An IPC(instrument panel Cluster) is a useful device that provides driving information to the driver. The information includes the vehicle speed, RPM, mileage, etc. The traditional IPC has been mostly implemented with mechanical technique. According to increment of needs for the convenience of IPC by user, the IPC must provide graphical interface and efficient driving information. Also the user-friendly IPC is needed by drivers. Thus flexible and robust software structure and development methods are required in order to develop IPC. In this paper, we propose software architecture and design method for the IPC using modeling method. We use MVC model and UML to model software architecture because they have flexible and robust characteristics. We can develop the various forms of information screen by separating views from model by using state diagram and class diagram in UML. Through this, the cost saving and ease of maintenance can be expected. The development time and cost can be reduced by using proposed method.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1321-1326
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• 2012

An IPC(instrument panel Cluster) is a useful device that provides driving information to the driver. The information includes the vehicle speed, RPM, mileage, etc. The traditional IPC has been mostly implemented with mechanical technique. According to increment of needs for the convenience of IPC by user, the IPC must provide graphical interface and efficient driving information. Also the user-friendly IPC is needed by drivers. Thus flexible and robust software structure and development methods are required in order to develop IPC. In this paper, we propose software architecture and design method for the IPC using modeling method. We use MVC model and UML to model software architecture because they have flexible and robust characteristics. We can develop the various forms of information screen by separating views from model by using state diagram and class diagram in UML. Through this, the cost saving and ease of maintenance can be expected. The development time and cost can be reduced by using proposed method.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.324-324
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• 2020

기후변화에 따른 기상 요소별 추세 변화는 유역유출량의 변동성을 증가시켜 안정적인 수자원 확보 및 홍수 대비에 어려움을 줄 수 있다. 따라서 기후변화에 따른 유역 유출량 변화를 평가하기 위한 많은 연구가 이루어져 왔다. 기존에는 기후변화 자료의 공간적 해상도의 한계로 인해 중대유역을 중심으로 연구가 다수 이루어져 왔으나, 최근 들어, 기후변화 자료의 공간적 상세화 기법이 발달함에 따라 소유역별 유역 유출량 평가에 관한 연구가 증가하고 있다. 특히, 소유역의 경우 유역 특성에 따라 기후변화에 따른 유출량 변화 민감도가 높을 수 있으며, 유출 성분별 변화가 상이할 수 있다. 하지만 기존의 연구에서는 소유역을 대상으로 기후변화에 따른 유출 성분별, 예를 들어 직접유출량과 기저유출량을 구분하여 변화를 평가하는 연구가 부족한 실정이다. 따라서 본 연구에서는 기후변화에 따른 소유역의 유출 성분별 특성을 분석하기 위하여, RCP 4.5, 8.5 시나리오별 기후모델 10개에 대하여 모의한 유출량을 직접유출량과 기저유출량으로 구분하고 결과를 비교 분석하였다. 본 연구의 대상지역은 유역면적이 112.9 ㎢이며, 토지이용이 단순하고, 농경지의 비율(약 50%)이 높은 농업 소유역을 대상으로 하였다. 유출량을 모의하기 위한 모형으로는 농업 소유역 유출량 모의 연구에 다수 사용된 바 있는 SWAT 모형을 이용하였으며, 직접유출량과 기저유출량의 분리는 Recursive Digital Filter 방법을 이용하였다. 기후변화 자료는 기후모델의 연산능력의 한계나 복잡한 자연조건의 불완전한 반영 등의 이유로 지역 기후변화 예측 과정에서 발생하는 불확실성을 지니고 있으므로 RCP 4.5, 8.5 시나리오별 각각 10개 기후모델의 결과를 이용하여 유출 특성 분석에 활용하였다. 본 연구의 결과는 향후 소유역의 미래 유량특성을 파악하기 위한 기초 자료로 활용될 수 있을 것으로 사료된다.

• The KIPS Transactions:PartA
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• v.8A no.1
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• pp.16-26
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• 2001

This paper proposes an extended scheduler model that is an extension of the existing model proposed already in [4, 5], which consists of upper layer task scheduler and lower layer scheduling framework. However, in order to support aperiodic task scheduling, the task scheduler has been divided into two parts, such as periodic task control component and aperiodic task control component. Thus, the proposed model can support various bandwidth-preserving servers that can service aperiodic tasks. The model distinctly separates a classic monolithic kernel scheduler into several kernel components according to their functionality. This enables system developers to implement a new scheduling algorithm or aperiodic task server independent of complex low kernel mechanism, and reconfigure the system at need. In Real-Time Linux [6], we implemented the proposed scheduling framework representative scheduling algorithms, and server bandwidth-preserving servers on purpose to test. Throughout these implementations, we confirmed that a new algorithm or server could be developed independently without updates of complex low kernel modules. In order to verify efficiency of the proposed model, we measured the performance of several aperiodic task servers. The results showed this the performance of model, which even consisted of two hierarchical components and several modules, didnt have such high run-time overhead, and could efficiently support reconfiguration and scheduler development.

• Journal of the Korean Geotechnical Society
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• v.32 no.9
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• pp.51-62
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• 2016

Parametric studies for various site conditions by using 3d numerical model were carried out in order to estimate dynamic behavior of soil-pile-structure system in dry soil deposits. Proposed model was analyzed in time domain using FLAC3D which is commercial finite difference code to properly simulate nonlinear response of soil under strong earthquake. Mohr-Coulomb criterion was adopted as soil constitutive model. Soil nonlinearity was considered by adopting the hysteretic damping model, and an interface model which can simulate separation and slip between soil and pile was adopted. Simplified continuum modeling was used as boundary condition to reduce analysis time. Also, initial shear modulus and yield depth were appropriately determined for accurate simulation of system's nonlinear behavior. Parametric study was performed by varying weight of superstructure, pile length, pile head fixity, soil relative density with proposed numerical model. From the results of parametric study, it is identified that inertial force induced by superstructure is dominant on dynamic behavior of soil-pile-structure system and effect of kinematic force induced by soil movement was relatively small. Difference in dynamic behavior according to the pile length and pile head fixity was also numerically investigated.

• Journal of Astronomy and Space Sciences
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• v.20 no.4
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• pp.239-248
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• 2003

We completed the light curves of near-contact binary system AX Dra for 11 nights from March 2001 to May using the 61-cm reflector and VR filters at Sobaeksan Optical Astronomy Observatory. From our observations, seven new times of minimum light (three timings to. primary eclipse, four. for. secondary) and the light elements consistent with recent observations were determined. Using the Wilson-Devinney binary code and the q-search method, we analyzed our VR light curves for various Roche configurations and mass ratios. As the results, we found the eclipsing binary AX Dra to be the FO Vir-type near-contact binary system interpreted as a detached or a semi-detached system, with the secondary filling its Roche lobe and the primary almost. Unlike the statistical study(Shaw 1994) of the FO Vir-type near-contact binary system, our VR light curves showed the O'Connell effect of all the same type and it's dimensions was about $0^{m}.008$.

• Journal of Astronomy and Space Sciences
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• v.6 no.2
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• pp.101-108
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• 1989

The algorithm was developed for the estimation of orbital decay of the Soviet Satellite COMOS 1402 which divides into three body-COSMOS 14020-A, B and C-and fell down early in 1983. The perturbation effects due to the nonspherical geopotential and air drag were considered and the standard atmospheric model were built for obtaining the atmospheric density as a function of the height. The orbital elements of NASA GSFC during orbital decay used in estimation of orbital decay. We compared the estimation values with the published ones of the American State Department. In the case of COSMOS 1402-C, the estimated values accorded with the published ones but, in the case of COSMOS 1402-A, the decay time and the approximated position differed respectively one minute and two degrees in both latitude and longitude from the published ones.