• Journal of Broadcast Engineering
• /
• v.4 no.2
• /
• pp.144-154
• /
• 1999

The binomial sequences are family of orthogonal sequences that can be generated with remarkable simplicity-no multiplications are necessary. This paper introduces a class of non-recursive multidimensional filters for frequency-selective image processing without multiplication operations. The magnitude responses are narrow-band. approximately gaussian-shaped with center frequencies which can be positioned to yield low-pass. band-pass. or high-pass filtering. Algorithms for the efficient implementation of these filters in software or in hardware are described. Also. we show that the binomial QMFs are the maximally flat magnitude square Perfect Reconstruction paraunitary filters with good compression capability and these are shown to be wavelet filters as well. In wavelet transform the original image is decomposed at different scales using a pyramidal algorithm architecture. The decomposition is along the vertical and horizontal direction and maintains constant the number of pixels required to describe the images. An efficient perfect reconstruction binomial QMF-Wavelet signal decomposition structure is proposed. The technique provides a set of filter solutions with very good amplitude responses and band split. The proposed binomial QMF-filter structure is efficient, simple to implement on VLSl. and suitable for multi-resolution signal decomposition and coding applications.

• Journal of Korea Spatial Information System Society
• /
• v.12 no.1
• /
• pp.49-56
• /
• 2010

Many researches of frequent pattern mining technique for detecting unknown patterns on spatial data have studied actively. Existing data structures have classified into tree-structure and array-structure, and those structures show the weakness of performance on dense or sparse data. Since spatial data have obtained the characteristics of dense and sparse patterns, it is important for us to mine quickly dense and sparse patterns using only single algorithm. In this paper, we propose novel data structure as compressed patricia frequent pattern tree and frequent pattern mining algorithm based on proposed data structure which can detect frequent patterns quickly in terms of both dense and sparse frequent patterns mining. In our experimental result, proposed algorithm proves about 10 times faster than existing FP-Growth algorithm on both dense and sparse data.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.1
• /
• pp.18-23
• /
• 2006

Flutter analysis of NACA 0012 with Gurney flap was conducted in time domain. Flutter analysis was performed with a conjunction of two governing equations; one is 2D Navier-Stokes equation and, the other is Lagrange equation of two dimensional plunge & pitch model. Both governing equations were coupled by loose-coupling method. From the computed results, the effect of Gurney flap was concluded to move the flutter boundary of NACA 0012 downward, which means flutter occurs at lower speed than that of NACA 0012. Although flutter boundary of gurney flap was above the safety margin when mach number was lower than 0.85, there might be a possibility of crossing the safety margin when mach number was between 0.85 and 0.9. For safety, the effect of gurney flap needs to be investigated carefully before using it.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2005.10a
• /
• pp.336-342
• /
• 2005

Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete.

• Journal of the Korean Magnetics Society
• /
• v.4 no.4
• /
• pp.319-325
• /
• 1994

Permalloy films were deposited by an RF magnetron sputtering method using several different targets which had been cold-rolled and annealed at various temperatures to give different microstructure and texture. The grain refinement occurs at high temperature annealing due to recrystallization and subsequently the initial (110) target texture transforms to the random texture. The coercive forces of thin films fabricated using targets which are not recrystallized are below 0.2 Oe in the AI pressure range of 1~5 mTorr and the lowest coercive force achieved is 0.07 Oe. The low value of coercive force, 0.25 Oe, is only obtained at the sputtering conditions of 400 W and 1 mTorr, and 300 W and 5 mTorr when recrystallized targets are used. The internal stress changes from compressive to tensile as the Ar pressure increases, the stress-free being at 5 mTorr. The changes of coercive force and permeability can be well interpreted by the differences from the composition and the internal stress.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.6
• /
• pp.37-45
• /
• 2015

In this experimental study, effect of milled glass fibers was investigated on corrosion resistance of PSC grout mortar. In order to check whether the mortar mixture with milled glass fibers satisfy the required properties as a PSC grout, time of flow, bleeding and compressive strength measured. The corrosion resistance were investigated through chloride ion migration test, mortar absorption test and surface resistivity measurement. It is confirmed that all proportions with milled glass fibers have better corrosion resistance than that with only OPC binder. Time of flow was reduced but the bleeding was increased to unacceptable level by using milled glass fibers. Consequently, the mix proportion with milled glass fibers for a PSC grout should be modified to have lower water/binder ratio.

• Elastomers and Composites
• /
• v.12 no.2
• /
• pp.157-164
• /
• 1977

(1) 탄성체(彈性體) MBMA를 가황제(加黃劑)로 사용한 가황체(加黃體)는 MOCA를 가황제(加黃劑)로 한 것 보다 Pot life가 긴 것이 특징(特徵)이다. 물리적(物理的) 특성(特性)에 있어서는 2가지 공(共)히 비승하였으나, 내열성(耐熱性)은 MOCA의 경우가 더 우수(優秀)하였다. 인장강도(引張强度), 신장률(伸張率), 반발탄성(反潑彈性)에 있어서는 MBMA를 사용(使用)한 가황(加黃體)와 MOCA를 사용(使用)한 가황체(加黃體)가 동일(同一)하였으나 압축(壓縮)줄음율은 전자(前者)가 높았다. 인열강도(引裂强度)에 있어서는 10부(部)의 MBMA를 가(加)했을 때 후자(後者)와 동일(同一)하였다. 또 MBIA 가황제(加黃劑)를 사용하였을 경우 인장강도(引張强度), 신장률(伸張率) 그리고 반발탄성등(反潑彈性等)이 MBMA 또는 MOCA의 경우와 거의 동일(同一)하였으나 고무가 부드러운 것이 특징이었다. 다만 100% 모듈러스의 경우 전자(前者)가 후자(後者)들보다 낮은 값이었다. NCO와 OH의 비(比)가 2 : 1인 Prepolymer를 사용한 MBIA가황체(加黃體)(MBIA를 가황제(加黃劑)로 한 가황체(加黃體))는 MBMA 가황체(加黃體) 또는 MOCA 가황체(加黃體)에 비(比)해 인열강도(引裂强度)는 낮았다. 그러므로 인열강도(引裂强度)를 향상(向上)시키기 위하여 NCO와 OH의 비(比)를 2 : 1보다 높은 비율(比率)로 취(取)하면 된다. 내열성(耐熱性)에 있어서 MBIA가황체(加黃體)가 MOCA가황체(加黃體)보다 우수(優秀)하였 고 또 배합작업(配合作業)에 있어서도 MOCA나 MBMA 가황체(加黃體)보다 작업성(作業性)이 용역(容易)하였는 바 이같은 이유(理由)는 전자(前者)의 녹는 점(點)$(70^{\circ}C)$이 후자(後者)들보다 낮기 때문이다. MBIA의 기타(其他) 특성(特性)으로서는 Pot life가 MOCA가황체(加黃體)보다 2.5배(倍) 길었다. 끝으로 MBEHA와 MBCHA가황체(加黃體)의 특징(特徵)은 가황속도(加黃速度)가 MBIA가황체(加黃體)보다 느림과 동시(同時)에 고무자체(自體)가 부드러웠을 뿐만 아니라 물리적(物理的) 특성(特性)도 좋지 않았다. (2) 미세구조용(微細構造用) 포옴라버 미세구조용((微細構造用) 포옴라버를 제조(製造)할 경우 이때까지 사용(使用)해온 MOCA가황제(加黃劑) 대신(代身) MBMA를 가황제(加黃劑)로 대체사용(代替使用)이 가능(可能)한 바, 이를 사용(使用)하였을 때의 물리적(物理的) 특성(特性)은 MOCA를 사용(使用)하였을 때 보다 인열강도(引裂强度), 신장률(伸張率) 그리고 열안정성등(熱安定性等)은 월등(越等)히 우수(優秀)하였다.

• The KIPS Transactions:PartB
• /
• v.12B no.7 s.103
• /
• pp.755-760
• /
• 2005

To transmit a video bit stream over low bandwith, such as mobile, channels, encoding algorithms for high bit rate like H.263+ are used. In transmitting video bit-streams, packet losses cause severe degradation in image quality. This paper proposes a new algorithm for the recovery of missing or erroneous motion vectors when H.263+ bit-stream is transmitted. Considering that the missing or erroneous motion vectors are closely related with those of neighboring blocks, this paper proposes a temporal-spatial error concealment algorithm. The proposed approach is that missing or erroneous Motion Vectors(MVs) are recovered by clustering the movements of neighboring blocks by their homogeneity. MVs of neighboring blocks we clustered according to ALA(Average Linkage Algorithm) clustering and a representative value for each cluster is determined to obtain the candidate MV set. By computing the distortion of the candidates, a MV with the minimum distortion is selected. Experimental results show that the proposed algorithm exhibits better performance in subjective and objective evaluation than existing methods.

• Journal of Biosystems Engineering
• /
• v.9 no.2
• /
• pp.97-113
• /
• 1984

날씨가 더운지방에 소규모(小規模) 목장(牧場)들이 먼거리를 두고 산재(散在)되어 있는 경우, 각목장(各牧場)에서 생산(生産)된 우유(牛乳)를 수집(收集)해서 처리공장(處理工場)까지 수송하는 데는 많은 어려움이 있다. 현대화(現代化)된 우유처리공장(牛乳處理工場)이나 저온저장시설이 충분(充分)하지 못한 아열대지방(亞熱帶地方)에 위치(位置)한 발전도상국에서는 우유(牛乳)를 장시간(長時間) 수집(收集)하여 먼거리를 수송하는 동안 많은 양(量)의 우유(牛乳)가 부패 손실(損失)되고 있다. 이 문제를 해결(解決)하기 위하여, 그곳 현지목장(現地牧場)에 강하게 쪼이는 태양열(太陽熱)을 이용(利用)하는 것은 대단히 바람직 하다. 에너지 절약이나, 우유(牛乳)의 부패손실(腐敗損失) 막기 위하여, 태양열(太陽熱)을 이용(利用)한 소규모우유처리기(小規模牛乳處理機)를 개발하여 현지목장(現地牧場)에서 직접(直接) 우유를 처리(處理)하여 인근주민에게 공급하는 것이 가장좋은 해결방법이라 판단하고, 그 실현가능성을 확인(確認)하기 위하여 실제로 태양열(太陽熱)우유처리기(處理機) 개발(開發)을 위한 그 모형(模型)의 회로구성(回路構成)을 고찰(考察)한 결과(結果) 다음과 같다. 1. 태양열(太陽熱) 우유처리기(牛乳處理機)의 모형(模型)은 다음 4개(個)의 회로(回路)로 구성(構成)되었다. 가. 우유(牛乳)순환 회로(回路) 나. 가열회로(加熱回路) 다. 예냉회로(豫冷回路) 라. 냉각회로(冷却回路) 2. 우유가열회로(牛乳加熱回路)는 태양열(太陽熱)을 이용(利用)하였으며 냉각회로(冷却回路)는 압축식 냉각기(冷却機)를 이용(利用)하였다. 3. 자동제어(自動制御)시스템을 장치(裝置)하여 태양강도변화(太陽强度變化)에 따른 우유처리량(牛乳處理量) 조절(調節)을 자동화(自動化)할 수 있도록 하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.6
• /
• pp.3667-3671
• /
• 2015

Through experiment that does not cause wrinkles in the forming process for the primary purpose for install PCB(Printed circuit board) the thickness variation of the material was investigated. Experimental results was showed that the forming height of the first process had Influence Material thickness variation in the second process, in the first process, the Entrance corner of the die must have round of the product height of 50%, and The height of forming should be as high as the thickness of the material than the original forming. Also as do implement the forming shape in the first process, the thickness of the material is thinned to 85%, Restriking in the second process was that The thickness of the material is thinned to 80%. Therefore, In order to implement a precise shape, Thinking that the material thinning, The die was maintain the shape of the original product, and It was obtain the effect of the compression that the punch is to be longer, as the sum of more than 20% of the material thickness in the depth of the original product.