• Title/Summary/Keyword: Threshold Point

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A Fast Ground Segmentation Method for 3D Point Cloud

  • Chu, Phuong;Cho, Seoungjae;Sim, Sungdae;Kwak, Kiho;Cho, Kyungeun
    • Journal of Information Processing Systems
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    • v.13 no.3
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    • pp.491-499
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    • 2017
  • In this study, we proposed a new approach to segment ground and nonground points gained from a 3D laser range sensor. The primary aim of this research was to provide a fast and effective method for ground segmentation. In each frame, we divide the point cloud into small groups. All threshold points and start-ground points in each group are then analyzed. To determine threshold points we depend on three features: gradient, lost threshold points, and abnormalities in the distance between the sensor and a particular threshold point. After a threshold point is determined, a start-ground point is then identified by considering the height difference between two consecutive points. All points from a start-ground point to the next threshold point are ground points. Other points are nonground. This process is then repeated until all points are labelled.

The Comparative Study on the Effect of Trigger Point Treatment, Self-Exercise Treatment, Trigger Point - Self-Exercise Cooperative Treatment for Neck Pain Caused by Traffic Accidents (교통사고 후 경항통 발생환자 중 Trigger Point 치료군, 자가운동 치료군, Trigger Point 및 자가운동 병행 치료군 비교연구)

  • Lee, Hyun-Jae;Park, Jung-Oh;Oh, Min-Seok
    • Journal of Korean Medicine Rehabilitation
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    • v.24 no.2
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    • pp.131-140
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    • 2014
  • Objectives This study was aimed at comparing clinical effectiveness among trigger point treatment, Self-exercise treatment, trigger point - self-exercise cooperative treatment for neck pain caused by traffic accidents. Methods 63 patients with neck pain by traffic accidents were divided into 3 groups. Different types of treatments were carried out for each groups ; group A with trigger point, group B with self-exercise, group C with trigger point and self-exercise cooperative treatment. 3 groups were also treated with general acupuncture and herb-medicine treatment. Pain threshold, visual analogue scale (VAS), and neck disability index (NDI) were checked on a daily basis. SPSS ver. 18.0 for Windows was used for analysis of data. The effectiveness of treatment of each groups were verified by using paired test and one-way repeated-measures ANOVA test, and the comparison of VAS, NDI and pain threshold were demonstrated by independent samples t-test. Results 3 groups all showed significant difference in pain threshold, VAS and NDI after 8 days later. Group C showed more improvement in pain threshold, VAS and NDI than shown in group A and B. In the first period (from pre-treatment to 4th day treatment) group C showed significant difference in NDI and pain threshold but not in VAS as compared to group A and B. In the second period (from 4th treatment to 8th day treatment), Group C showed significant difference in pain threshold, VAS and NDI as compared to group A and B. Conclusions Trigger point - self-exercise cooperative treatment is proved to be more helpful to improve the unstability and reduce neck pain than trigger point treatment or self-exercise treatment only, therefore eventually leading to better satisfaction for patients with neck pain.

Agglomeration (Dis-) Economies and Regional Economic Growth as a Spatial Economy (집적 (불)경제와 공간경제로서의 지역 경제 성장)

  • 김홍배;박재룡
    • Journal of the Korean Regional Science Association
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    • v.13 no.2
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    • pp.45-54
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    • 1997
  • A regional economy is characterized as a spatial economy. However the literature shows that it has been treated as a point economy since space is little recognized in regional modeling due to mathematical complication. This leads to the fact that regional model does not sufficiently represent regional characteristic. This paper attempts to construct a regional growth model in a partial equilibrium framework specifically taking into consideration land as a primary factor. The model is formulated largely neoclassical. Labor is assumed to move in response to differences in the wage rate, while capital is perfectly mobile across regions. The paper shows that two growth equilibrium points exist, one stable equilibrium point and the other unstable equilibrium point. The unstable growth equilibrium indicates the existence of minimum threshold that a region must overcome the minimum threshold to grow constantly. Consequently, directions of regional growth are characterized by two growth paths depending on the initial condition of a region. That is to say, a region below the minimum threshold is converging toward the lower stable equilibrium point over time. When a regional economy initially lies above the minimum threshold, it will grow forever. A regional economy is not thus necessarily converging a stationary is not thus necessarily converging a stationary equilibrium point through factor movement. Finally, the impacts of the presence of agglomeration economies and diseconomies are analyzed through the phase diagram. The paper also shows that agglomeration economies result in lowering the minimum threshold and in escalating the level of stable equilibrium However, when agglomeration diseconomies prevail, the results are opposite, i.e., rising the minimum threshold of growth and lowering the growth level of stable equilibrium.

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Effects on Pressure Pain and Tactile Threshold by Auricular TENS at Shenmen Point (신문 반응점에 적용한 외이 경피신경전기자극이 압통각 및 촉각역치에 미치는 영향)

  • Jung, Dae-In
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.2 no.1
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    • pp.59-70
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    • 2004
  • The purpose of this study were to determine the changes between pre, during, intermed, post of each two groups of 16 persons and to compare the effect of transcutaneous electrical nerve stimulation(TENS) at shenmen of auricular point on experimental pressure pain and tactile threshold measured at both ulnar styloid process and medial malleoli. Sixteen healthy adult men and women, aged 20 to 28 years, were assigned randomly to eight of one groups. Control group received TENS to exception of auricular point. Experimental group received TENS to shenmen of auricular point. Experimental pressure pain and tactile pain threshold at the both ulnar styloid process and medial malleoli was determined with algometer and von frey filament before 10 minute, during 10 minute, intermediate and post 30 min of treatment. In pressure pain and tactile threshold showed a statistically significant increase(p<0.05) ipsilateral and contralateral of treatment group. These results suggest that TENS at shenmen of auricular point has the capability to higher pressure pain and tactile threshold in whole body.

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Effects of Transcutaneous Electrical Nerve Stimulation and Laser at Auricular Points on Experimental Cutaneous Pain Threshold (외이에 대한 경피신경 전기자극과 레이저가 실험적 피부 통증역치에 미치는 영향)

  • Sim, Youn-Ju;Lee, Mi-Sun;Lee, Yun-Ju
    • Physical Therapy Korea
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    • v.4 no.1
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    • pp.87-94
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    • 1997
  • The purposes of this study were 1) to determine the changes between pre-treatment and post-treatment of four groups of 15 persons each and 2) to compare the effect of conventional transcutaneous electrical nerve stimulation(TENS) and laser at auricular acupuncture points on experimental pain threshold measured at the wrist. Sixty healthy adult men and women(M:32, F:28), aged 20 to 28 years, were assigned randomly to one of four groups. Group 1 received TENS to the appropriate auricular point for wrist pain, Group 2 received laser to the appropriate auricular point for wrist pain, Group 3 received placebo TENS to the appropriate auricular point for wrist pain, Group 4 received no treatment and served as controls. Experimental pain threshold at the wrist was determined with a painful electrical stimulus before and 20 minutes after ear stimulation. Group 1 was the only group that showed a stastically significant increase (p<0.05) in pain threshold after treatment whereas the Group 2,3 and 4 did not. These results suggest that TENS has the capability to higher pain threshold but laser does not.

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The effects of Breif, Intense Transecutaneous Electrical Nerve Stimulation on Nerve conduction, Pain Threshold in Healthy subjects (Brief, Intense TENS 자극이 신경전도, 통증역치의 변화에 미치는 효과)

  • Kim Tae-Youl;Hwang Tae-Yeun;Huh Choon-Bok
    • The Journal of Korean Physical Therapy
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    • v.6 no.1
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    • pp.171-183
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    • 1994
  • Purphose. This present study examines the effect of brief, intense transcutaneous electrical nerve stimulation(BTENS) on sensory nerve conduction, electrical pain threshold, and two-point discrimination measured at the superficial radial nevre distribution in 20 healthy subjects. Subjects. Twenty volunteercs, (10 females and 10 males(age range : 20-38 years : $mean{\pm}SD\;:\;27.00{\pm}5.12$), only subjects without prior traumatological and pathological were eligible to participated in this study. Methods. Nerve conduction were determined for the right superficial radial nerve. Electrical pain threshold were determined for the right wrist ipsilateral to the site of BTENS. Small disc electrodes were attached to the surface of the skin stradding the end of the radius. Square wave electrical pulses were delivered from an isolated stimulator through a constant current device at a frequency of 2 Hz(5 ms pulse width). Two-point discrimination, measured on the sensory distribution of superficial radial nerve. BTENS was delivered using a Max-SD( Medical design co.) portable battery powered stimulator. A cicular Ag/AgCl electrode in contact with hypertonic saline gel was attached to the lateral(radial side) surface of the forearm. Results. No significant effects were observed between stimulation methods in the prestimulation cycle(multi-way ANOVA repeated measures : distal latency ; F1.14=0.332. amplitude ; F 0.80=0.445, pain threshold ; F0.06=0.940.2 point discrimination ; F1.50=0.236). Highly significant effects were observed time with the pretreatment and 6 posttreatment cycles(p<0.01). Mighty significants differences in nerve conduction and pain threshold were found using un multi-way ANOVA repeated measures among stimulation methods for each cycles(p<0.01). Conclusion and Discussion The authors concludes that both nerve conduction and pain threshold changes are associated with therapy (stimulation) level of BTENS.

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The Use of Skin Resistance Point Finder for the Diagnosis of Myofascial Trigger Points (피부 저항점 탐지기를 사용한 근근막 통증 유발점의 진단)

  • Kang, Mi-Suk;Hong, Jung-Eun;Lim, Young-Jin;Lee, Sang-Chul
    • The Korean Journal of Pain
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    • v.12 no.2
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    • pp.195-199
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    • 1999
  • Background: At present, there is no reliable objective test for the diagnosis of myofascial trigger points (MFTP). We evaluated the usefulness of skin resistance point finder for the diagnosis of MFTP. Methods: 40 subjects with clinical MFTPs at the upper trapezius muscle were included in this study. Using skin resistance point finder (UNIQUE S-2010$^{(R)}$, Seik medical, Korea), we tried to find out the point of low skin resistance. At three different current level, sensitivity and specificity of this method for the diagnosis of clinically identified MFTP was evaluated. Pressure threshold for pain of low skin resistance point was measured using Pressure Threshold Meter$^{(R)}$ (Pain Diagnostics and Thermography, U.S.A.). 3 groups of point detected at different current were compared in mean pressure threshold. Results: Fixed single current of skin resistance point finder showed variable sensitivity and specificity. But, by adjusting current level, skin resistance point finder detected all of 40 clinically identified MFTPs. Although it is partially statistically significant, the mean pressure threshold of points detected at high current was high. Conclusion: Skin resistance finder can be used as objective diagnostic tool of MFTPs. There is possibility that it can be useful in evaluating treatment effect. However, more investigation is necessary.

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Two optimal threshold criteria for ROC analysis

  • Cho, Min Ho;Hong, Chong Sun
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.1
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    • pp.255-260
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    • 2015
  • Among many optimal threshold criteria from ROC curve, the closest-to-(0,1) and amended closest-to-(0,1) criteria are considered. An ROC curve that passes close to the (0,1) point indicates that two models are well classified. In this case, the ROC curve is located far from the (1,0) point. Hence we propose two criteria: the farthest-to-(1,0) and amended farthest-to-(1,0) criteria. These criteria are found to have a relationship with the KolmogorovSmirnov statistic as well as some optimal threshold criteria. Moreover, we derive that a definition for the proposed criteria with more than two dimensions and with relations to multi-dimensional optimal threshold criteria.

Adaptive Key-point Extraction Algorithm for Segmentation-based Lane Detection Network (세그멘테이션 기반 차선 인식 네트워크를 위한 적응형 키포인트 추출 알고리즘)

  • Sang-Hyeon Lee;Duksu Kim
    • Journal of the Korea Computer Graphics Society
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    • v.29 no.1
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    • pp.1-11
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    • 2023
  • Deep-learning-based image segmentation is one of the most widely employed lane detection approaches, and it requires a post-process for extracting the key points on the lanes. A general approach for key-point extraction is using a fixed threshold defined by a user. However, finding the best threshold is a manual process requiring much effort, and the best one can differ depending on the target data set (or an image). We propose a novel key-point extraction algorithm that automatically adapts to the target image without any manual threshold setting. In our adaptive key-point extraction algorithm, we propose a line-level normalization method to distinguish the lane region from the background clearly. Then, we extract a representative key point for each lane at a line (row of an image) using a kernel density estimation. To check the benefits of our approach, we applied our method to two lane-detection data sets, including TuSimple and CULane. As a result, our method achieved up to 1.80%p and 17.27% better results than using a fixed threshold in the perspectives of accuracy and distance error between the ground truth key-point and the predicted point.

Initial Investigation on Consolidation with Adaptive Dynamic Threshold for ABR Multicast Connections in ATM Networks (비동기 전송모드 망의 점대다중점연결을 위한 적응동적임계치기반 병합알고리즘)

  • Shin, Soung-Wook;Cho, Kwang-Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.11
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    • pp.962-966
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    • 2001
  • The major problem at a branch point for point-to-multipoint available bit rate(ABR) services in asynchronous transfer mode (ATM) networks is how to consolidate backward resource management(BRM) cells from each branch for a multicast connection. In this paper, we propose an efficient feedback consolidation algorithm based on an adaptive dynamic threshold(ADT) to eliminate the consolidation noise and the reduce the consolidation delay. The main idea of the ADT algorithm lies in that each branch point estimates the ABR traffic condition of the network through the virtual queue estimation and the transmission threshold of the queue level in branch points is adaptively controlled according to the estimation. Simulation results show that the proposed ADT algorithm can achieve a faster response in congestion status and a higher link utilization compared with the previous works.

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