• 융합신호처리학회논문지
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• 제19권4호
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• pp.199-205
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• 2018

기존의 전영역 탐색 방법의 많은 계산량으로 인하여 예측 화질 향상과 연산량 감축을 위한 연구가 진행되어 왔으며, 본 논문에서는 전영역 탐색기반의 방법과 비교하여 예측화질은 거의 유지하면서 효율적으로 계산량을 줄이는 방법을 제안한다. 제안하는 알고리즘은 다중 문턱치 필터를 이용하여 각 후보 지점에 대하여 부분 블록 에러 합을 계산하고, 이를 여러 문턱치 필터에 적용하여 각 후보들을 영역별로 분류 또는 제거하고, 이에 따라 다음 단계에서 진행할 후보들을 선별하고, 최소 에러지점의 최적후보에 대해 단계별 부동 회수를 비교 판단하여 그 다음 단계의 진행 여부를 결정함으로써 최적의 움직임 벡터를 고속으로 계산한다. 이를 통하여 전체의 최소블록매칭에러를 갖는 움직임 벡터를 조기에 발견하고, 불필요한 후보들을 더 빨리 제거함으로써 불필요한 계산량을 줄이고 계산속도 향상을 얻을 수 있다. 또한 제안하는 알고리즘은 단독으로 사용할 뿐만 아니라 기존의 고속 알고리즘들과 결합하여 사용해도 예측화질대비 우수한 연산량 감소를 얻을 수 있으며, 실험결과에서 이를 검증한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.347-351
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• 2007

The influence of compaction pressure and sintering temperature on the hydraulic cylinder block fabricated by powder metallurgy is investigated in this study. The cylinder block is powder compacted under various compaction pressures and sintered under various sintering temperatures, and its density and dimensions are measured to reveal the relation of the process condition with the product quality. Moreover, finite element analyses of the density distributions are conducted under the same conditions with the experiments and the predicted results are compared with the measured ones.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.293-298
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• 2002

Recycling of coal combustion by-product(Ash) are becoming more improtant in the utilization business as a result of the increased use of NOx reduction technologies at coal-fired power plants. current disposal methods of these by-products create not only a loss of profit for the power industry, but also environmental concerns that breed negative public opinion. This research made concrete crecast block using coal ash artificial aggregate for environmental-friendly products and compared strength special quality of this block with existent common use brick and analyzed application possibility in situ with a reserve experiment that measured strength property and manufactured method to handle coal ash produced in Bo-ryung thermoelectric power plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.748-750
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• 2004

The pantograph should supply the electrification equipments of a train with the current from the overhead catenary system over a broad range of speeds. For a high-speed electrical train, the dynamic interaction between the pantograph and the overhead catenary system causes the variation of the contact force. As the operational speed increases, the variation of the contact force increases. The contact force variation can cause contact losses, arcing and sparking. If the spark happens between the pantograph and the overhead catenary system, the EMI(electro magnetic interface) and noises may occur. After all, the quality of current collection is deteriorated. This paper deals with the dynamic characteristics analysis between pantograph and catenary system using block pulse function.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권8호
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• pp.1964-1981
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• 2012

In this paper a reversible data hiding scheme based on histogram shifting of host image blocks is presented. This method attempts to use full available capacity for data embedding by dividing the image into non-overlapping blocks. Applying histogram shifting to each block requires that extra information to be saved as overhead data for each block. This extra information (overhead or bookkeeping information) is used in order to extract payload and recover the block to its original state. A method to eliminate the need for this extra information is also introduced. This method uses maximum gap that exists between histogram bins for finding the value of pixels that was used for embedding in sender side. Experimental results show that the proposed method provides higher embedding capacity than the original reversible data hiding based on histogram shifting method and its improved versions in the current literature while it maintains the quality of marked image at an acceptable level.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권11호
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• pp.2941-2956
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• 2013

In this paper, we propose an effective fragile image watermarking scheme for tampering detection and content recovery. Cover image is divided into a series of non-overlapping blocks and a block mapping relationship is constructed by the secret key. Several DCT coefficients with direct current and lower frequencies of the MSBs for each block are used to generate the reference bits, and different coefficients are assigned with different bit numbers for representation according to their importance. To enhance recovery performance, authentication bits are generated by the MSBs and the reference bits, respectively. After LSB substitution hiding, the embedded watermark bits in each block consist of the information of itself and its mapping blocks. On the receiver side, all blocks with tampered MSBs can be detected and recovered using the valid extracted reference bits. Experimental results demonstrate the effectiveness of the proposed scheme.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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• pp.157-160
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• 1998

KS F 4419, which is dealt with the Inter-Locking block, states that water to cement ratio for manufacturing inter-locking block should be less than 25% and in KS F4419, the use of admixture is shown to be reluctant to recommend. In this paper, reinvestigation of some regulations in KS F 4419 are carried out. According to the experimental results, as W/C increases, flexural strength and compressive strength are tended to decrease, whereas they increases within certain range, Flexural strength and compressive strength have higher values in 1:2(W/C=35%), 1:4(W/C=45%) and 1:6(W/C=55%) of mix proportions. Moreover they have rather higher values with the containment of high range AE water-reducing agent. The absorption ratios decrease with the increase of W/C and the containment of high range AE water-reducing agent. Therefore, the regulations on the W/C and admixture in KS F 4419 reguire revision.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.1015-1020
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• 2002

Recycling of coal combustion by-product(Ash) are becoming more improtant in the utilization business as a result of the increased use of NOx reduction technologies at coal-fired power plants. Current disposal methods of these by-products create not only a loss of profit for the power industry, but also environmental concerns that breed negative public opinion. This research made Precast block for environment-friendly secondary product and compare strength special quality of this block with existent common use brick and analyze application possibility in situ with a reserve experiment that measure strength property and manufacture method to handle coal ash produced in Bo-ryung thermoelectric power plant.

• 한국정보처리학회논문지
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• 제7권7호
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• pp.2254-2263
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• 2000

This paper proposes an efficient predictive image-compression technique based on vector quantization of blocks of pels. In the proposed method edge contents of blocks control the selection of predictors and block shapes as well. The maximum number of bits assigned to quantizers has been in creased to 3bits/pel from 1/5bits/pel, the setting employed by forerunners in predictive vector quantization of images. This increase prevents the saturation in SNR observed in their results in high bit rates. The variable block shape is instrumental in eh reconstruction of edges. The adaptive procedure is controlled by means of he standard deviation ofp rediction errors generated by a default predictor; the standard deviation address a decision table which can be set up beforehand. eh proposed method is characterized by overall improvements in image quality over A-VQ-PE and A-DCT VQ, both of which are known for their efficient use of vector quantizers.

• The Korean Journal of Pain
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• 제3권2호
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• pp.172-176
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• 1990

In Incheon Severance Hospital, a secondary delivery hospital, anesthesiologists have treated cancer pain in the operation room when referred from other department. Intrathecal neurolytic block is a valuable means of producing high quality pain relief in any hospital. It is simple to carry out, requires brief hospitalization, can be used in elderly or severely ill patients, can be repeated with the block wears off and its duration is sufficient for the terminal cancer patients. We reviewed the clinical charateristics of the intrathecal alcohol and phenol-glycerine used in two cases of cancer with pain.