• Title, Summary, Keyword: segments

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Effect of Polymerization Procedure on Thermal and Mechanical Properties of Polyether Based Thermoplastic Polyurethanes

  • Kim, Seong-Geun;Lee, Dai-Soo
    • Macromolecular Research
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    • v.10 no.6
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    • pp.365-368
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    • 2002
  • Thermoplastic polyurethanes (TPUs) with different hard segment length has been prepared from a fixed molar ratio of poly(tetramethylene ether glycol), 4,4'-diphenylmethane diisocyanate, and 1,4-butanediol by different polymerization procedures. Results reveal that the on-set temperature of endotherms ( $T_{cc}$ ) due to the crystallization of hard segments by cooling the TPUs from melt and the peak temperature of endotherms due to the melting of hard segments ( $T_{mh}$ ) by heating the TPUs increased and levelled off with increasing the hard segment length of TPUs. It has also been observed that soft segment glass transition temperature ( $T_{gs}$ ) of TPU decreased slightly with increasing the hard segment length, which explains less mixing of soft segments and hard segments. In tensile measurement of TPUs, strain hardening is observed with increasing the hard segment length, which is attributed to the strain induced crystallization of soft segments.

An Adaptive and Robust Inspection Algorithm of PCB Patterns Based on Movable Segments (동적 세그먼트 기반 PCB 패턴의 적응 검사 알고리즘)

  • Moon Soon-Hwan;Kim Gyung-Bum
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.3
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    • pp.102-109
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    • 2006
  • Several methods for PCB pattern inspection have been tried to detect fine detects in pad contours, but their low detection accuracy results from pattern variations originating from etching, printing and handling processes. The adaptive inspection algorithm has been newly proposed to extract minute defects based on movable segments. With gerber master images of PCB, vertex extractions of a pad boundary are made and then a lot of segments are constructed in master data. The pad boundary is composed of segment units. The proposed method moves these segments to optimal directions of a pad boundary and so adaptively matches segments to pad contours of inspected images, irrespectively of various pattern variations. It makes a fast, accurate and reliable inspection of PCB patterns. Its performances are also evaluated with several images.

Waveform Detection Algorithm based on the Search of Distinctive Line-Segments (검색에 기초한 파형 검출 알고리듬)

  • 박승훈;장태규
    • Journal of Biomedical Engineering Research
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    • v.14 no.3
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    • pp.265-272
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    • 1993
  • We present a new waveform detection method, based on the search of distinctive line-segments. The method is based on the basic assumption that the waveform morphology of biological signals is readily characterized by a sequence of the distinctive line-segments and their structural features. In this method, the distinctive line-segments are first searched for, and a structural feature analysis is performed an the distinctive line-segments found. Experiments of detecting epileptic spikes were carried out to evaluate the detection per formance of the method. Two subjects were used for training and tuning the algorithm and four subjects for testing the method. The results were obtained on two different performance indices, detection ratio and the number of false detections per minute.

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Android Application for Connecting Cycling Routes on Strava Segments

  • Mulasastra, Intiraporn;Kao-ian, Wichpong
    • Journal of information and communication convergence engineering
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    • v.17 no.2
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    • pp.142-148
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    • 2019
  • Relatively few countries provide separate bicycle lanes for cyclists. Hence, tools for suggesting cycling routes are essential for a safe and pleasant cycling experience. This study aims to develop a mobile application to build cycling routes based on user preferences, specifically location, search radius, ride distance, and number of optimal routes. Our application calls the Strava API to retrieve Strava cycling segments crowdsourced from the cycling community. Then, it creates a graph consisting of the start and end points of these segments. Beginning from a user-specified location, the depth-first search algorithm (DFS) is applied to find routes that conform to the user's preferences. Next, a set of optimal routes is obtained by computing a trade-off ratio for every discovered route. This ratio is calculated from the lengths of all segments and the lengths of all connecting paths. The connected routes can be displayed on a map on an Android device or exported as a GPX file to a bike computer. Future work must be performed to improve the design of the user interface and user experience.

Vertex-based shape coding based on the inter-segment distance (블록간 상대거리에 의한 정점기반 모양정보 부호화 기법)

  • 이진학;정재원;문주희;김재균
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.7A
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    • pp.1017-1027
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    • 2000
  • In this paper, we propose a new coding method based on the distance between vertex segments for vertex positions in the vertex-based shape coding. The pixel lines are divided into the segments of a fixed length, and the segments that have vertex pixels are called vertex segments. We analyze the probability distribution of the relative distance between vertex segments and prove that it depends only on the ratio between the number of vertices and the number of segments. Considering the coding efficiency and implementation complexity, we choose a particular ratio to make a code table. For each input image, the segment size is chosen according tothe ratio, and the relative segment distances are entropy coded. It is shown that the proposed method is efficient for the images with many vertices.

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An Analysis of the Hazardous Highway Segments Using Continuous Risk Profile Method (고속도로 사고잦은 지점 분석방법 연구)

  • Lee, Soo-Il;Yu, Jun-Seok
    • Journal of the Korean Society of Safety
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    • v.25 no.6
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    • pp.180-185
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    • 2010
  • We have to develop more correct and systematic way to choose Hazardous Highway Segments. In this research, we applied CRP(Continuous Risk Profile) technique which developed by UC Berkeley Traffic Safety Center in year of 2007, and can analyze yearly dangerous level tendency of continuity in the route of main road that is under California Department of Transportation(Caltrans). We changed standard of CRP to suit in Korean circumstance with consideration in radius of curve and traffic volume. For the verification by actual accident data, we embodiment the CRP by using the data from total of 587 case of accident in latest 10 years in Gyeong-Bu Highways, the amount of 56km. Finally, the effectiveness of technique in this research has been verified by obtained same result with current method for Hazardous Highway Segments. In addition, when calculating the Hazardous Highway Segments with technique that presented in this research we obtained following statements. First, identified dangerous level of continuity in the route by using CRP. Second, Accurate of Actual Hazardous Highway Segments selection has been developed by using last 10 year's data and profile making which provide simplicity analyze of Tendency. Third, after reforming the way of selection, effective range has been wider than former selection and it gives advantage for the policy side.

Arc/Line Segments-based SLAM by Updating Accumulated Sensor Data (누적 센서 데이터 갱신을 이용한 아크/라인 세그먼트 기반 SLAM)

  • Yan, Rui-Jun;Choi, Youn-sung;Wu, Jing;Han, Chang-soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.10
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    • pp.936-943
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    • 2015
  • This paper presents arc/line segments-based Simultaneous Localization and Mapping (SLAM) by updating accumulated laser sensor data with a mobile robot moving in an unknown environment. For each scan, the sensor data in the set are stored by a small constant number of parameters that can recover the necessary information contained in the raw data of the group. The arc and line segments are then extracted according to different limit values, but based on the same parameters. If two segments, whether they are homogenous features or not, from two scans are matched successfully, the new segment is extracted from the union set with combined data information obtained by means of summing the equivalent parameters of these two sets, not combining the features directly. The covariance matrixes of the segments are also updated and calculated synchronously employing the same parameters. The experiment results obtained in an irregular indoor environment show the good performance of the proposed method.

Predictive Values of Gated Myocardial SPECT for Wall Motion Improvement After Bypass Surgery (게이트 심근 SPECT의 관동맥우회로술후 심근 벽운동 호전 예측능)

  • Lee, Dong-Soo;Yoon, Seok-Nam;Song, Ho-Cheon;Kim, Ki-Bong;Chung, June-Key;Lee, Myoung-Mook;Lee, Myung-Chul;Koh, Chang-Soon
    • The Korean Journal of Nuclear Medicine
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    • v.31 no.1
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    • pp.43-49
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    • 1997
  • We studied to investigate the predictive values of gated SPECT for the improvement of wall motion after bypass surgery. As we compared postoperative SPECT with preoperative ones, we defined viability as wall motion improvement. We peformed rest T1-201/s1ress Tc-99m-MIBI gated SPECT in 25 patients before and 3 months after bypass surgery. Myocardial wall motion was graded as normal, hypokinesia, akinesia, and dyskinesia by pair-wise visual analysis of gated pre and postoperative SPECT's on the same monitor screen. Myocardial wall thickening was determined good or poor Among 92 segments with wall motion abnormalities before operation, 69 (75%) improved and 23 did not. Before operation, we could find segments with good systolic thickening in 64 segments among total 92. Thickening of the remaining 28 was poor. Wall motion improved postoperatively in 45 segments (70%) among 64 with good thickening. Twenty four(86%) among 28 segments with poor thickening had also improved. We grouped segments into mild(hypokinetic) and severe(akinetic/dyskinetic) ones. Among 33 segments with severe motion abnormalities, 14 had good thickening and 19 did not. Nine(60%) improved out of 14 segments having severe abnormality with good thickening However, 16(84%) segments out of 19 haying severe abnormality with poor thickening also improved. Neither degree of perfusion decrease nor severity of wall motion abnormalities could explain the high rate of false negatives. In conclusion, as we defined viability as wall motion improvement by comparing pre and postoperative SPECT, systolic thickening observed by gated Tc-99m-MIBI SPECT in myocardial segments with wall motion abnormalities predicted wall motion improvement after bypass surgery. However, poor thickening could not be referred as evidence of nonviable myocardium both in mild and severe contractile dysfunction, so that we might need stimulation study such as dobutamine echocardiography or dobutamine gated SPECT.

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Histological and histochemical studies of the squirrel epididymis (다람쥐 부고환의 조직학적 및 조직화학적 연구)

  • Ryu, Si-yun;Cho, Sung-whan;Kim, Moo-kang;Kim, Sung-ho;Lee, Cha-soo
    • Korean Journal of Veterinary Research
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    • v.29 no.3
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    • pp.215-222
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    • 1989
  • In order to investigate the morphological characteristics of epididymal duct of the squirrel, the histological and histochemical studies were carried out. The results obtained were summarized as follows: The epididymal duct can be divided into 9 segments by histological and histochemical features. Segments 1 to 5 were located in the head, segments 6 and 7 in the body, and segments 8 and 9 in the tail of the epididymis. The apical cells were numerous in the segment 1. Clear cells which has a compact, deeply staining nucleus and a characteristically clear cytoplasm were scattered in the epithelium throughout the duct. Interepithelial clear cells which had PAS-positive granules tended to increase in number caudally. Strong PAS-positive reaction was detected at the intralumen of the segments 3,8 and 9. Acid phosphatase activity was relatively high in the basal cytoplasm of the segment 7, and then in the supranuclear region of the segments 8 and 9. Alkaline phosphatase activity was weakly positive or negative except the segments 3 and 4. ATPase activity was strong in the free surface of the epithelium in the head and the entire cytoplasm in the body and tail, a,nd SDH activity was generally weak except for the body where it was more intense.

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Study on improving method of arranging trapezoidal pre-cast segment lining in shield tunnel (쉴드터널의 사다리꼴 세그먼트라이닝 배열방법 개선에 대한 연구)

  • Kim, Jung-Hyun;Kang, Kyung-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.9 no.1
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    • pp.1-18
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    • 2007
  • This study is about an arrangement method of trapezoidal pre-cast segment lining that can be applied in shield tunnel construction. Trapezoidal segment lining is formed by assembling tapered pre-cast concrete segments taking advantage of the tapered shape of pre-cast segments upon delivery on site. By calculating tapering of the segments manufactured in single type and rotating the segments when putting them together, a variety of tunnel alignments can be arranged in the most efficient way. Once the design criteria and tunnel alignment (straight or curved) is analyzed, the sequence of assembling trapezoidal segments in compliance with tunnel alignment will be computed. On site an operator can utilize the softwareto automatically determine sequential arrangement of trapezoidal segments. When the actual arrangement of segmental lining is different from the computed output, the operator can input the actually measured values to coincide the computerized calculation with the real status of assembly. Then the adjustment will be the basis of subsequent arrangement of segments, thus the continuity of work can be guaranteed.

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