• 대한전기학회논문지
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• 제35권11호
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• pp.511-518
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• 1986

An algorithm for block-decomposition of a linear, time-invariant, discrete large-scale systems is presented, based upon the matrix sign function on Z-plane. The block-decomposition is performed by defining a reference circle, a circular stripe and projection operators. Simulation study shows that the presented algorithm is very useful for multivariable control system's analysis and design.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(3)
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• pp.75-78
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• 2002

In this paper, we present the design and implementation of a Fault Tolerant VOD system. The system uses the double striping policy that a original file is sequentially striped to multiple streaming server with constant data block size and the data block of one streaming server is re-striped to the other streaming server. When a fault occurs in one streaming server, automatically the other streaming server will service.

• 대한건축학회논문집:구조계
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• 제35권4호
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• pp.157-165
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• 2019

Recently, lean duplex stainless steel, STS329FLD with less nickel (reduced to 0.5~1.5%) has been developed as a substitute of austenitic stainless steel (8%~10.5% nickel in STS304) and included in Korean standards (KS). This paper investigates the block shear behavior of cold-formed duplex stainless steel (STS329FLD, nominal plate thickness of 1.5mm) fillet-welded connection with base metal fracture. Main variables are weld lengths in the longitudinal and the transverse directions of applied force ranged from 20mm to 50mm. As a result, specimens failed by typical block shear facture (the combination of gross section tensile fracture and shear fracture or shear yielding) and ultimate strength of the specimens got higher with the increase of weld length. Block shear fracture strengths predicted by current design specifications (KBC2016/AISC2016 and EC3) and existing proposed equations for welded connections by Topkaya, Oosterhof & Driver and Lee et al. were compared with test strengths. KBC2016/AISC2016 and EC3 design specifications underestimated block shear strength of STS329FLD welded connections by on average 24%, 29%, respectively and Oosterhof & Driver, Topkaya and Lee et al's equations overestimated the ultimate strength of the welded connection by the range of 3% to 44%.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.822-826
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• 2008

A linkage mechanism is a device to convert an input motion into a desired output motion. Traditional linkage mechanism designs are based on trial and error approaches so that size or shape changes of an original mechanism often result in improper results. In order to resolve these problems, an improved automatic mechanism synthesis method that determines the linkage type and dimensions by using an optimization method during the synthesis process has been proposed. For the synthesis, a planar linkage is modeled as a set of rigid blocks connected by zero-length translational springs with variable stiffness. In this study, the sizes of rigid blocks were also treated as design variables for more general linkage synthesis. The values of spring stiffness and the size of rigid block yielding a desired output motion at the end-effecter are found by using an optimization method.

• Hip & pelvis
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• 제35권2호
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• pp.63-72
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• 2023

The aim of this study was to conduct a meta-analysis of randomized controlled trials (RCTs) for comparison of the effectiveness of pericapsular nerve group (PENG) block with that of other analgesic techniques for reduction of postoperative pain and consumption of opioids after total hip arthroplasty (THA). A search of records in the PubMed, Embase, and Cochrane Library, and ClinicalTrials.gov databases was conducted in order to identify studies comparing the effect of the PENG block with that of other analgesics on reduction of postoperative pain and consumption of opioids after THA. Determination of eligibility was based on the PICOS (participants, intervention, comparator, outcomes, and study design) criteria as follows: (1) Participants: patients who underwent THA. (2) Intervention: patients who received a PENG block for management of postoperative pain. (3) Comparator: patients who received other analgesics. (4) Outcomes: numerical rating scale (NRS) score and opioid consumption during different periods. (5) Study design: clinical RCTs. Five RCTs were finally included in the current meta-analysis. Significantly lower postoperative opioid consumption at 24 hours after THA was observed in the group of patients who received the PENG block compared with the control group (standard mean difference=-0.36, 95% confidence interval -0.64 to -0.08). However, no significant reduction in NRS score at 12, 24, and 48 hours after surgery and opioid consumption at 48 hours after THA was observed. The PENG block showed better results for opioid consumption at 24 hours after THA compared with other analgesics.

• ETRI Journal
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• 제20권1호
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• pp.16-27
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• 1998

In this paper, we consider the acquisition performance of an IS-95 reverse link access channel slot as a function of system design parameters such as postdetection integration length and the number of access channel message block repetitons. The uncertainty region of the reverse link spreading codes compared to that of forward link is very small, since the uncertainty region of the reverse link is determined by a cell radius. Thus, the parallel acquisiton technique in the reverse link is more efficient than a serial acquisition technique in terms of implementation and of acquisition time. The parallel acquisition is achieved by a bank of N parallel I/Q noncoherent correlator are analyzed for band-limited noise and the Rayleigh fast fading channel. The detection probability is derived for multiple correct code-phase offsets and multipath fading. The probability of no message error is derived when rake combining, access channel message block combining, and Viterbi decoding are applied. Numerical results provide the acquisition performance for system design parameters such as postdetection integration length and number of access channel message block repetitions in case of a random access on a mobile station.

• 대한건축학회논문집:계획계
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• 제35권6호
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• pp.27-37
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• 2019

This study focused on the possibility of reducing the cooling load through the change of micro climate in the outdoor space during summer season. This study proposes an efficient planning model by comparing the effects of urban heat island mitigation through wind path planning, outdoor space vegetation, and exterior material change by using the basic model of the street-oriented block housing proposed in the previous research by the same author. As a result, the most effective wind path planning strategy in the street-oriented block housing was the change of the air flow through the mass height adjustment. When the tall building masses were staggered and arranged in a balanced manner, the overall wind environment could be improved. The greater the height difference between low and high masses, the better the air flow was shown. It was also important to arrange the building masses so that the inlet of the main wind was open and to allow the external space to connect to the adjacent block to create a continuous flow. The change of outdoor space vegetation and flooring, and the formation of wind paths through the opening of lower part also showed the effect of heat island reduction. In addition, the change of PMV in summer was the biggest influence of shadow by tall building mass. Attention should be paid to the fact that high-albedo exterior materials are adversely affected by multiple reflections in dense street-oriented block housing. The use of albedo of the exterior material showed that it is necessary to pay attention to apply in the high density block housing. This is attributed to the rise of the temperature due to the absorption of energy into the low-albedo flooring, where the high-albedo exterior causes multiple reflections.

• International Journal of Fluid Machinery and Systems
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• 제8권3호
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• pp.142-154
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• 2015

Nowadays, computational fluid dynamics is commonly used by design engineers to evaluate and compare losses in hydraulic components as it is less expensive and less time consuming than model tests. For that purpose, an automatic tool for casing and distributor analysis will be presented in this paper. An in-house mesh generator and a Reynolds Averaged Navier-Stokes equation solver using the standard $k-{\omega}$ shear stress transport (SST) turbulence model will be used to perform all computations. Two solvers based on the C++ OpenFOAM library will be used and compared to a commercial solver. The performance of the new fully coupled block solver developed by the University of Lucerne and Andritz will be compared to the standard 1.6ext segregated simpleFoam solver and to a commercial solver. In this study, relative comparisons of different geometries of casing and distributor will be performed. The present study is thus aimed at validating the block solver and the tool chain and providing design engineers with a faster and more reliable analysis tool that can be integrated into their design process.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권6호
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• pp.440-445
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• 2004

The design and implementation of a Network Processor using System-on-a-chip(SoC) technology is presented. The proposed network processor can handle several protocols as well as various types of traffics simultaneously. The proposed SoC consists of ARM processor core, ATM block, AAL processing block, Ethernet block and a scheduler. The scheduler guarantees QoS of the voice traffic and supports multiple AAL2 packet. The SoC is manufactured on the 0.35 micron fabrication line of HYNIX semiconductor, the total number of gates is about 312,000, for a maximum operating frequency of over to 50㎒.

• 응용통계연구
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• 제2권1호
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• pp.54-64
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• 1989

Kurkjian 과 Zelen(1963)에 의해 조화행렬에서 행결합 행렬의 특성에 관계된 성질(Property) A가 제안되었다. 한편으로 Paik(1985)은 조화행렬이 블럭행렬로 분할되고, 분할된 블럭행렬간, 블럭행렬내에서 각각 순환하는 다중순환형식행렬을 갖는 경우를 정의하고, Paik(1985)은 이러한 특성을 갖는 계획을 성질 C라 하였다. 본 논문에서는 다중순환형식행렬을 갖는 조화행렬의 구조에 의하여 불완비블럭계획을 분류하였으며 분류의 목적은 축소된정규방정식의 해와 배치계획을 쉽게 하는데 있다.