• 제목/요약/키워드: multi-level accumulation

검색결과 31건 처리시간 0.024초

A Multi-Level Accumulation-Based Rectification Method and Its Circuit Implementation

  • Son, Hyeon-Sik;Moon, Byungin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권6호
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    • pp.3208-3229
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    • 2017
  • Rectification is an essential procedure for simplifying the disparity extraction of stereo matching algorithms by removing vertical mismatches between left and right images. To support real-time stereo matching, studies have introduced several look-up table (LUT)- and computational logic (CL)-based rectification approaches. However, to support high-resolution images, the LUT-based approach requires considerable memory resources, and the CL-based approach requires numerous hardware resources for its circuit implementation. Thus, this paper proposes a multi-level accumulation-based rectification method as a simple CL-based method and its circuit implementation. The proposed method, which includes distortion correction, reduces addition operations by 29%, and removes multiplication operations by replacing the complex matrix computations and high-degree polynomial calculations of the conventional rectification with simple multi-level accumulations. The proposed rectification circuit can rectify $1,280{\times}720$ stereo images at a frame rate of 135 fps at a clock frequency of 125 MHz. Because the circuit is fully pipelined, it continuously generates a pair of left and right rectified pixels every cycle after 13-cycle latency plus initial image buffering time. Experimental results show that the proposed method requires significantly fewer hardware resources than the conventional method while the differences between the results of the proposed and conventional full rectifications are negligible.

Radicular Compression by Intraspinal Epidural Gas Bubble Occurred in Distant Two Levels after Lumbar Microdiscectomy

  • Lee, Chul-Woo;Yoon, Kang-Jun;Ha, Sang-Soo;Kang, Joon-Ki
    • Journal of Korean Neurosurgical Society
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    • 제56권6호
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    • pp.521-526
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    • 2014
  • The authors report a case of symptomatic epidural gas accumulation 2 weeks after the multi-level lumbar surgery, causing postoperative recurrent radiculopathy. The accumulation of epidural gas compressing the dural sac and nerve root was demonstrated by CT and MRI at the distant two levels, L3-4 and L5-S1, where vacuum in disc space was observed preoperatively and both laminectomy and discectomy had been done. However, postoperative air was not identified at L4-5 level where only laminectomy had been done in same surgical field, which suggested the relationship between postoperative epidural gas and the manipulation of disc structure. Conservative treatment and needle aspiration was performed, but not effective to relieve patient's symptoms. The patient underwent revision surgery to remove the gaseous cyst. Her leg pain was improved after the second operation.

다단계 바이러스 차단 구조 연구 (Multi-level Protection Infrastructure for Virus Protection)

  • 노시춘;김귀남
    • 한국사이버테러정보전학회:학술대회논문집
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    • 한국사이버테러정보전학회 2004년도 제1회 춘계학술발표대회
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    • pp.187-198
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    • 2004
  • virus방역 체계 관리는 network infra구조관리, traffic소통경로관리. 방역 zone설정, gateway구간 방역관리이다. 본 논문은 일반적인 방역체계 구조의 성격과 취약점을 진단하고 이를 개선할 수 있는 대책으로서 개선된 방역체계를 설계하였다. 또한 설계된 방역체계와 configuration, mechanism하에서는 어느 정도의 개선효과 나타나고 있는지 분석하였다. 개선된 다단계 방역체계 하에서는 gateway 단계에서 불필요한 mail을 걸러주므로서 server에 주는 부하는 감소하며 virus wall상의 CPU부하의 감소와 virus 치료율의 상승으로 송신 적체 건수는 감소하고 시스템 process수는 증대하고있다.

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경계 영역에서 색 번짐 감소를 위한 멀티레벨 벡터 오차 확산법 (Multi-level Vector Error Diffusion for Smear Artifact Reduction in the Boundary Regions)

  • 박태용;조양호;김윤태;하영호
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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    • pp.461-464
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    • 2003
  • This paper proposes the multi-level vector error diffusion for smear artifact reduction in the boundary regions. Smear artifact mainly results from a large accumulation of quantization error. Accordingly, to reduce these artifacts, the proposed method excludes the large quantization error in the error diffusion process by comparing the magnitude of the error vector with predetermined first threshold. In addition, if the vector norm of the difference between the error adjusted input vector and the primary co]or that has minimum vector norm for the error adjusted input vector is larger than second threshold, the error is excluded. As a result, the proposed method reduce smear artifact in the boundary region and produces visually pleasing halftone pattern.

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Role of Integrin-Linked Kinase in Multi-drug Resistance of Human Gastric Carcinoma SGC7901/DDP Cells

  • Song, Wei;Jiang, Rui;Zhao, Chun-Ming
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권11호
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    • pp.5619-5625
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    • 2012
  • Gastric carcinoma is a leading cause of cancer death in the world and multi-drug resistance (MDR) is an essential aspect of gastric carcinoma chemotherapy failure. Recent studies have shown that integrin-linked kinase (ILK) is involved in metastasis of human tumors, expression silencing of ILK inhibiting the metastasis of several types of cultured human cancer cells. However, the role and potential mechanism of ILK to reverse the multi-drug resistance in human gastric carcinoma is not fully clear. In this report, we focused on roles of expression silencing of ILK in multi-drug resistance reversal of human gastric carcinoma SGC7901/DDP cells, including increased drug sensitivity to cisplatin, cell apoptosis rates, and intracellular accumulation of Rhodamine-123, and decreased mRNA and protein expression of multi-drug resistance gene (MDR1), multi-drug resistance-associated protein (MRP1), excision repair cross-complementing gene 1 (ERCC1), glutathione S-transferase -${\pi}$ (GST-${\pi}$) and RhoE, and transcriptional activation of AP-1 and NF-${\kappa}B$ in ILK silenced SGC7901/DDP cells. We also found that there was a decreased level of p-Akt and p-ERK. The results indicated that ILK might be used as a potential therapeutic strategy to combat multi-drug resistance through blocking PI3K-Akt and MAPK-ERK pathways in human gastric carcinoma.

복합재료의 피로손상 모형 및 다응력 수위 피로수명 예측 연구 (II) - 참고계수를 이용한 피로 손상 모형 - (Study on Fatigue Damage Model and Multi-Stress Level Fatigue Life Prediction of Composite Materials (II) -Fatigue Damage Model using Reference Modulus-)

  • 이창수;황운봉;한경섭
    • Composites Research
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    • 제12권2호
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    • pp.62-69
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    • 1999
  • 복합재료가 피로하중을 받으면 재료 내부에 손상이 누적되며, 이는 재료의 물성 변화로 나타난다. 본 연구에서는 손상을 나타내는 인자로 피로계수를 사용하였다. 피로계수와 참고계수로 정의되는 손상함수로부터 복합재료의 피로수명 예측을 이론적으로 연구하였다. 제안된 모델들은 인가 응력 수준, 피로주기 및 피로수명의 함수로 유도하였다. 예측 결과는 유리섬유/에폭시 복합재료와 유리섬유/폴리에스터 복합재료를 사용한 다중응력 피로 실험 데이터를 이용하여 검증하였다.

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고려(高麗) 금동탑(金銅塔)을 통해 본 법주사(法主寺) 팔상전(捌相殿)의 구조형식계통(構造形式系統) (The Structural Lineage of Palsangjeon in Pubjoo Temple Analyzed through Gilt-bronze Pagoda in the Koryo Period)

  • 김경표
    • 건축역사연구
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    • 제14권1호
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    • pp.89-105
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    • 2005
  • The central aim of this thesis is to see if the structure of Palsangjeon(捌相殿) in Pubjoo Temple(法住寺), a five sto wooden pagoda in Chosen(朝鮮) Dynasty, was handed down from the ancient and middle ages. This study was performed through an analysis of Gilt-Bronze Pagoda built in Koryo(高麗) period. In other words, it is aimed at analyzing which lineage the structure of Palsangjeonbelongs to as a wooden pagoda. In analyzing the structure of Palsangjeon, I attempted to find out its source from the remains of Koryo period prior to the Chosen Dynasty. Examples are the Gilt-Bronze Pagoda, built during the Koryo period. I have also examined its relationship with other existing wooden pagodas and remains. The analysis of Palsangjeon, a five story wooden pagoda in Chosen Dynasty, focuses on the following: First, I explored the possibilities of whether the structure of Palsangjeon was newly invented in Chosen Dynasty, or if it had been derived from the wooden pagodas in the Koryo period. Secondly, I tried to find out if the stable vertical planes, with a great successive diminution ratio, were derived from the middle age, i.e. Koryo period. The results of the study of Palsangjeon through Gilt-Bronze Pagoda analysis are as follows: 1. The structure of Gilt-Bronze Pagoda, a wooden pagoda from the Koryo period, is roughly classified into the accumulation type, using pipe pillars, and the one story type using whole pillars. In the accumulation type, stories are connected in either a flat format or an intervening format. The Gilt-Bronze Pagoda is mainly composed of pipe pillars, with some whole pillars. However, the central pillar was omitted in the building structure. Generally, the upper and lower stories are connected by pipe pillars in a crutch format. All the pillars, whether they are pipe pillars or whole pillars, used Naiten(內轉) technology. The Eave supporter has the Haang type(下昻) and the Muhaang type(無下昻). In most cases, high balustrades are furnished, but few tables of high balustrades have been found. The slanting roof formats have been handed down from Paekche(百濟), Silla(新羅), or Koryo(高麗). However, the structure of the octagon is assumed to be derived from Koguryo(高句麗). The structure of the Gilt-Bronze Pagoda from the Koryo period is mainly composed of accumulated flat squares, with some spire types. intervening format, the structure of Palsangjeon used whole pillars in a half story format in which upper level side pillars are installed on the lower level tie beam. From the Bronze Pagoda from the Koryo period, we can assume that the half story format of wooden pagodas that has stable vertical planes with a great successive diminution ratio was created during the mid-Koryo period at the latest and had been idly developed by the time of the Chosen Dynasty. 3. The whole pillars in Palsangjeon are also found in Gilt-Bronze Pagodas from the Koryo period. Hence, all of the pillars in Palsangjeon seem to have been handed down from the ancient construction technology. They were also used in the construction of wooden pagodas from the Koryo period. Therefore, it is assumed that Palsangjeon was constructed using the construction technology of the Chosen Dynasty that had been developed from the wooden pagoda construction technology of the Koryo period. The stable vertical planes with a great successive diminution ratio in Palsangjeon are derived from ancient Korean wooden pagodas, which have developed into indigenous Korean wooden pagodas with fairly stable vertical planes and a great design, in the half story format of Koryo and Chosen Dynasty. Therefore, it is assumed that the structure of Palsangjeon has a systematic relationship with traditional Korean wooden pagodas and is one of the indigenous Korean wooden pagoda structures. 4. In China, the intervening format has been mainly used between stories in multi-story architecture since the ancient days. At the same time, the flat format as also used in ancient and middle ages. However, the flat format was replaced by whole pillars during the Ming(明) and Manchu(淸) Dynasties, in favor of simple and compact construction. The half-story format, in which upper level side pillars are installed on tie beams, has been found in some cases, but it doesn't seem to have been the primary construction technology. Few traces of the half-story format have been found in multi-story architecture in Japan, and it has not been used as a general construction format. By contrast, the half-story format, which seems to have been derived from the Koryo period, was used as a general construction format in multi-story architecture of the Chosen Dynasty. The construction technology of multi-story architecture is related to that of multi-story wooden pagodas, but they have different production technologies. It seems that the structure of Palsangjeon did not just adopt the construction technology of multi-story architecture in the Chosen Dynasty, but it was developed from wooden pagodas in the Koryo period, including the Gilt-Bronze Pagoda. 5. Since the ancient days, most Chinese and Japanese wooden pagodas have adopted an accumulation type of structure using pipe pillars, with accumulated pointed towers. On the other hand, though most Korean wooden pagodas have also adopted an accumulation type of structure from the ancientdays, one story type using whole pillars was created in the Koryo and Chosen Dynasties. The wooden pagoda structure of Palsangjeon, with stable vertical planes in a half story format, is a unique Korean construction technology, different from the construction technologies of Chinese and Japanese wooden pagodas. This thesis clearly determined the structural characteristics of Palsangjeon. However, various remains have yet to be analyzed in depth, to establish an accurate construction technology system. In the beginning of this thesis, I had difficulty in precisely interpreting the internal structure of the Gilt-Bronze Pagoda from its appearance. However, in the process of study, the more serious problem was that there are few remains or ruins of multi-story architecture in ancient and the middle ages of Korea. Therefore, it is urgent to discover various remains in the future. This thesis succeeded in determining the structural characteristics of Palsangjeon. However, it fell short of clarifying the structural lineage of the stable vertical planes, although they show indigenous Korean architectural taste, representing the unique national emotion, and the construction format of multi-story wooden pagodas in Korea. I hope this is clarified in the future research.

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Strain energy-based fatigue life prediction under variable amplitude loadings

  • Zhu, Shun-Peng;Yue, Peng;Correia, Jose;Blason, Sergio;De Jesus, Abilio;Wang, Qingyuan
    • Structural Engineering and Mechanics
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    • 제66권2호
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    • pp.151-160
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    • 2018
  • With the aim to evaluate the fatigue damage accumulation and predict the residual life of engineering components under variable amplitude loadings, this paper proposed a new strain energy-based damage accumulation model by considering both effects of mean stress and load interaction on fatigue life in a low cycle fatigue (LCF) regime. Moreover, an integrated procedure is elaborated for facilitating its application based on S-N curve and loading conditions. Eight experimental datasets of aluminum alloys and steels are utilized for model validation and comparison. Through comparing experimental results with model predictions by the proposed, Miner's rule, damaged stress model (DSM) and damaged energy model (DEM), results show that the proposed one provides more accurate predictions than others, which can be extended for further application under multi-level stress loadings.

The Optimized Design of a NPC Three-Level Inverter Forced-Air Cooling System Based on Dynamic Power-loss Calculations of the Maximum Power-Loss Range

  • Xu, Shi-Zhou;He, Feng-You
    • Journal of Power Electronics
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    • 제16권4호
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    • pp.1598-1611
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    • 2016
  • In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

Air Pollution Tolerance and Heavy Metal Accumulation of Selected Tree Species at Swamp Forest Research Station, Onne, Rivers State

  • Rosemary Egodi Ubaekwe;Victoria Amarachi Okpara;Uzoma Darlington Chima
    • Journal of Forest and Environmental Science
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    • 제40권3호
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    • pp.227-240
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    • 2024
  • Trees improve air quality through the accumulation of air pollutants in their leaves; however, the responses of different tree species to air pollution varies. Hence, this study evaluated the responses to air pollution of selected tree species in the Swamp Forest Research Station, Onne. Ten tree species (Cola pachycarpa, Khaya grandifoliolia, Irvingia gabonensis, Garcinia kola, Chrysophyllum albidum, Treculia africana, Dacryodes edulis, Tectonia grandis, Gmelina aborea, and Nauclea diderrichii) were selected based on their abundance in the area. Leaves were collected from all sides in 3 replicates for each tree species. Laboratory analysis was carried out using standard procedures. Portable Multi Gas Detector was used to determine the concentrations of air pollutants. One-way analysis of variance was employed to test for significant difference (p≤0.05) in biochemical parameters among the tree species while Pearson's correlation was utilized to determine the level of association between different biochemical parameters and APTI; heavy metals and APTI. Results showed high concentration of PM10, CO, moderate concentration of NO2, PM2.5, and VOC, and low concentration of ground O3. Heavy metals - Cadmium, Mercury, Lead, Nickel and Copper were all present in the tree species at varying rates. There were significant differences in the biochemical parameters and APTI values. C. pachycarpa exhibited the highest APTI value (89.88), while D. edulis had the lowest APTI value (8.24). C. pachycarpa, K. grandifoliolia, C. albidum, G. kola, T. africana, and N. diderrichii were identified as tolerant tree species to air pollution. G. aborea, T. grandis, and I. gabonensis were considered intermediate tolerant species, while D. edulis was the only tree species sensitive to air pollution. Ascorbic Acid, Chlorophyll, Hg and Ni had positive correlations with APTI; Cd and Cu had negative association with APTI at the 0.05 significance level. C. pachycarpa, T. africana, K. grandifoliolia, C. albidum, N. diderrichii and G. kola, are recommended for planting in pollution-prone areas.