• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4624-4642
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• 2014

Image compression is a popular research issue that focuses on the problems of reducing the size of multimedia files. Vector Quantization (VQ) is a well-known lossy compression method which can significantly reduce the size of a digital image while maintaining acceptable visual quality. A locally adaptive scheme (LAS) was proposed to improve the compression rate of VQ in 1997. However, a LAS needs extra indicators to indicate the sources, consequently the compression rate of LAS will be affected. In this paper, we propose a novel method to eliminate the LAS indicators and so improve the compression rate. The proposed method uses the concept of data hiding to conceal the indicators, thus further improving the compression rate of LAS. From experimental results, it is clearly demonstrated that the proposed method can actually eliminate the extra indicators while successfully improving the compression rate of the LAS.

• Steel and Composite Structures
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• 제24권3호
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• pp.309-322
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• 2017

This paper conducted both numerical and theoretical studies to investigate the composite action of notched circular concrete-filled steel tubular (CFT) stub columns under axial compression and established a theoretical method to predict their ultimate bearing capacity. 3D finite element (FE) analysis was conducted to simulate the composite action and the results were in good agreement with experimental results on circular CFT stub columns with differently oriented notches in steel tubes. Parametric study was conducted to understand the effects of different parameters on the mechanical behavior of circular CFT stub columns and also the composite action between the steel tube and the core concrete. Based on the results, a theoretical formula was proposed to calculate the ultimate bearing capacity of notched CFT stub columns under compression with consideration of the composite action between the steel tube and the core concrete.

• Steel and Composite Structures
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• 제26권6호
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• pp.719-731
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• 2018

Concrete filled steel tubular (CFST) laced columns have been widely used in high rise buildings in China. Compared to solid-web columns, this type of columns has a larger cross-section with less weight. In this paper, four concrete filled steel tubular laced columns consisting of 4 main steel-concrete tubes were tested under cyclic loading. Hysteresis and failure mechanisms were studied based on the results from the lateral cyclic loading tests. The influence of each design parameter on restoring forces was investigated, including axial compression ratio, slenderness ratio, and the size of lacing tubes. The test results show that all specimens fail in compression-bending-shear and/or compression-bending mode. Overall, the hysteresis curves appear in a full bow shape, indicating that the laced columns have a good seismic performance. The bearing capacity of the columns decreases with the increasing slenderness ratio, while increases with an increasing axial compression ratio. For the columns with a smaller axial compression ratio (< 0.3), their ductility is increased. Furthermore, with the increasing slenderness ratio, the yield displacement increases, the bending failure characteristic is more obvious, and the hysteretic loops become stouter. The results obtained from the numerical analyses were compared with the experimental results. It was found that the numerical analysis results agree well with the experimental results.

• Archives of Plastic Surgery
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• 제50권1호
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• pp.70-81
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• 2023

Background The clinical results of conservative treatment options for ulnar compression at the elbow have not been clearly determined. The aim of this review was to evaluate available conservative treatment options and their effectiveness for ulnar nerve compression at the elbow. Methods In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, a systematic review and meta-analysis of studies was performed. Literature search was performed using Ovid MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL). Results Of the 1,079 retrieved studies, 20 were eligible for analysis and included 687 cases of ulnar neuropathy at the elbow. Improvement of symptoms was reported in 54% of the cases receiving a steroid/lidocaine injection (95% confidence interval [CI], 41-67) and in 89% of the cases using a splint device (95% CI, 69-99). Conclusions Conservative management seems to be effective. Both lidocaine/steroid injections and splint devices gave a statistically significant improvement of symptoms and are suitable options for patients who refuse an operative procedure or need a bridge to their surgery. Splinting is preferred over injections, as it shows a higher rate of improvement.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.167-170
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• 2000

Recently the sub-micron structured substrates of 0.74 ${mu}ell$ track pitch and 800 $\AA$groove depth are required for DVD-RAM and the track pitch is expected to be narrower as the need for the information storage density is getting higher. For the accurate replication of the land-groove structure in the stamper to the plastic substrates it is important to control the injection -compression molding process such that the integrity of the replication for the land-groove structure is maximized. in the present study polycarbonate substrates were fabricated by injection comression molding and the land-groove structure regarded as one of mold temperature and the compression pressure on the integrity of the replication were examined experimentally. An efficient design methodology using the response surface method (RSM) the central composite design(CCD) technique and the analysis-of-variance (ANOVA) was developed to obtain the optimum processing conditions which maximize the integrity of the replication with a limited number of experiments.

• Journal of Chest Surgery
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• 제34권12호
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• pp.972-975
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• 2001

선천성 횡격막 거상증은 우측이나 좌측 또는 양측으로 발생할 수 있다고 알려져 있다. 횡격막의 중앙부위와 우측 중앙 건삭부위에서 간 부엽에 의해 심장압박이 동반된 선천성 횡격막 거상증 환자가 있어 비디오 흉강경을 통한 횡격막 주름 성형술을 시행하였던 증례를 보고하고자 한다.

• Steel and Composite Structures
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• 제44권4호
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• pp.473-488
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• 2022

A high-speed railway (HSR) bridge may undergo long-term deformation due to the degradation of material stiffness, or foundation settlement during its service cycle. In this study, an analytical model is set up to evaluate the influence of this long-term vertical bridge deformation on the track geometry. By analyzing the structural characteristics of the HSR track-bridge system, the energy variational principle is applied to build the energy functionals for major components of the track-bridge system. By further taking into account the interlayer's force balancing requirements, the mapping relationship between the deformation of the track and the one of the bridge is established. In order to consider the different behaviors of the interlayers in compression and tension, an iterative method is introduced to update the mapping relationship. As for the validation of the proposed mapping model, a finite element model is created to compare the numerical results with the analytical results, which show a good agreement. Thereafter, the effects of the interlayer's different properties of tension and compression on the mapping deformations are further evaluated and discussed.

• 한국음향학회지
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• 제14권1호
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• pp.5-12
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• 1995

Training 벡터 집합이 Cluster를 이루는 경우, 벡터 양자화에서 영상과 음성의 압축에 사용되는 코드북의 코드벡터는 Cluster의 중심벡터로 간주된다. 본 연구에서는 Training 벡터 간의 Euclidean 거리가 최소가 되는 벡터를 찾는 과정에서 얻어지는 Euclidean 거리분포를 관찰하여 적절한 Cluster수와 그 중심벡터를 결정할 수 있는 방법을 제시하고, 제안된 방법이 기존의 LBG 알고리즘이나 Competitive 학습 알고리즘에 의한 영상 압축보다 약 4[dB] 이상 향상된 SNR을 얻을 수 있음을 보인다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.251-256
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• 2003

The detailed flow characteristics inside a compression chamber due to the orbiting motion of a scroll is studied numerically. The orbiting motion of a scroll is modelled at 7 orbiting angles. At each orbit angle, the central compression chamber is modelled. All computations are carried by using an in-house code. It is based on the SIMPLE algorithm. Computation results show that the flow structure inside the compression chamber is dependent on the orbit angle. The pressure variation inside the compression chamber also shows great dependence on the orbit angle. The pressure variation shows local maxima when the orbiting motion of a scroll directs toward the center of the compression chamber.

• 한국포장학회지
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• 제7권1호
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• pp.9-15
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• 2001

Top-to-bottom compression strength of corrugated fiberboard boxes is partly dependent on the load-carrying ability of the central panel areas. The ability of these central areas to resist bending under load will increase the stacking strength of the box. The difference of box compression strengths, among boxes which are made with identical dimensions and fabricated with same components but different flute sizes, is primarily due to difference of the flexural stiffness of the box panels. Top-to-bottom compression strength of a box is accurately predicted by flexural stiffness measurements and the edge crush test of the combined boards. This study was carried out to analyze the flexural stiffness, maximum bending force and maximum deflection for various corrugated fiberboards by experimental investigation. There were significant differences between the machine direction (MD) and the cross-machine direction (CD) of corrugated fiberboards tested. It was about 50% in SW and DW, and $62%{\sim}74%$ in dual-medium corrugated fiberboards(e.g. DM, DMA and DMB), respectively. There were no significant differences of maximum deflection in machine direction among the tested fiberboards but, in cross direction, DM showed the highest value and followed by SW, DMA, DMB and DW in order. For the corrugated fiberboards tested, flexural stiffness in machine direction is about $29%{\sim}48%$ larger than cross direction, and difference of flexural stiffness between the two direction is the lowest in DMA and DMB.