• Title/Summary/Keyword: positions

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The Effects of Foot Position on Electromyographic Activity of Knee Extensors in Standing (기립자세에서 발위치가 무릎 폄근의 등척성수축 근전도 활성도에 미치는 영향)

  • Kim, Seng-Jung;Kwon, Oh-Yun;Cho, Sang-Hyun;Hwang, Ji-Hye
    • Physical Therapy Korea
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    • v.8 no.2
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    • pp.1-16
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    • 2001
  • This study was designed to identify the effects of foot position on electromyographic (EMG) activity of the quadriceps femoris during maximum voluntary contraction (MVC) in standing. Twenty young adults who had not experienced any knee injuries were recruited. Their Q-angles were within a normal range. They were asked to stand in five different foot positions ($40^{\circ}$ externally rotated, $30^{\circ}$ internally rotated, neutral, $20^{\circ}$ plantarflexed, and $10^{\circ}$ dorsiflexed foot position). The EMG activities of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis oblique (VMO) were recorded in standing by surface electrodes and normalized by MVC EMG values derived from manual muscle test. The normalized EMG activity levels (%MVC EMG) of muscles in the five foot positions were compared using repeated measures ANOVA. The EMG activity levels of the VL, RF, and VMO were the highest when foot was externally rotated. The EMG activity levels of the VL and RF were significantly different among the foot positions (p<.05). However, EMG activity levels of the VL, RF, VMO, and VMO/VL ratio did not show significant differences in each foot position (p> .05). The results suggest that the quadriceps femoris may be effectively activated by performing MVC at an externally rotated foot position. Therefore, the externally rotated foot position can be considered as an effective foot position for quadriceps femoris strengthening exercise. Further studies are needed to identify whether there are differences in the effects of foot position on muscle strength after MVC exercise of quadriceps femoris in standing.

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Gaze Detection System by IR-LED based Camera (적외선 조명 카메라를 이용한 시선 위치 추적 시스템)

  • 박강령
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.4C
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    • pp.494-504
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    • 2004
  • The researches about gaze detection have been much developed with many applications. Most previous researches only rely on image processing algorithm, so they take much processing time and have many constraints. In our work, we implement it with a computer vision system setting a IR-LED based single camera. To detect the gaze position, we locate facial features, which is effectively performed with IR-LED based camera and SVM(Support Vector Machine). When a user gazes at a position of monitor, we can compute the 3D positions of those features based on 3D rotation and translation estimation and affine transform. Finally, the gaze position by the facial movements is computed from the normal vector of the plane determined by those computed 3D positions of features. In addition, we use a trained neural network to detect the gaze position by eye's movement. As experimental results, we can obtain the facial and eye gaze position on a monitor and the gaze position accuracy between the computed positions and the real ones is about 4.2 cm of RMS error.

An Indexing Scheme for Predicting Future-time Positions of Moving Objects with Frequently Varying Velocities (속도 변화가 빈번한 이동 객체의 미래 시점 위치 추정에 적합한 색인 기법)

  • Lim, Sung-Chae
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.5
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    • pp.23-31
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    • 2010
  • With the advances in the information technology and mobile communications, we now face increasing demands for various services based on both of position tracking of moving objects and their efficient index scheme. Accordingly, the $TPR^*$-tree, which were proposed for efficiently tracking moving objects and predicting their positions in the future time, has drawn much intention. As the $TPR^*$-tree came from the R-tree that is suitable for indexing static objects, it does not support cheap update costs. Therefore, it seems to be very costly to index moving objects if there are frequent occurrences of node updates caused by continuously changing velocities and positions. If some moving objects with high velocities have node updates, in particular, then the $TPR^*$-tree may suffer from many unnecessary updates in the wide range of tree regions. To avoid such a problem, we propose a method that can keep fast-moving objects in the child nodes of the root node, thereby saving node update costs in the $TPR^*$-tree. To show our performance advantages and retaining $TPR^*$-tree features, we performed some performance experiments using a simulation technique.

Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems

  • Park, Jong-Kyoung;Lee, Wan-Sun;Kim, Hae-Young;Kim, Woong-Chul;Kim, Ji-Hwan
    • The Journal of Advanced Prosthodontics
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    • v.7 no.2
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    • pp.122-128
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    • 2015
  • PURPOSE. To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. MATERIALS AND METHODS. Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (${\alpha}$=.05), respectively. RESULTS. The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). CONCLUSION. Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (< $120{\mu}m$). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.

Comparisons of Vastus Medialis and Vastus Lateralis EMG Onset Time During Quadriceps Strengthening Exercise in Neutral and Adducted Hip Positions (대퇴사두근 근력 운동 시 고관절 중립 자세와 내전 자세에 따른 내측광근과 외측광근의 근수축 개시 시간 차이 비교)

  • Choi, Bo-Ram;Kim, Min-Heem;Jeon, Hye-Seon
    • Physical Therapy Korea
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    • v.16 no.3
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    • pp.42-49
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    • 2009
  • This study examined the vastus medialis oblique (VMO) and the vastus lateralis (VL) onset time differences (OTD) during quadriceps contraction in different hip positions. Twelve healthy subjects were recruited (four men, eight women). Surface EMG activities of the VMO and VL were measured during a quadriceps strengthening exercise in a long sitting condition and in a sitting at a chair with feet hanging condition. For each condition, subjects were tested in two hip positions (neutral and adduction). The OTD between the two muscles was calculated for each condition, by subtracting the onset time of the VL from the VMO. Therefore, the negative value of OTD represent earlier EMG onset of the VMO compared to the VL. The OTD was not significantly different between the hip neutral and the hip adduction position in the long sitting condition (p=.064). However, the OTD was significantly different between the hip neutral position ($15.83{\pm}109.51$ ms) and hip adduction position ($-5.58{\pm}121.08$ ms) during the sitting at a chair with feet hanging condition (p=.047). The negative OTD value in the hip adduction condition during quadriceps strengthening exercises is the result of earlier onset of the VMO than VL. Therefore, quadriceps contraction in the hip adduction position can prevent the risk of patella lateral tracking. We expect that quadriceps strengthening exercise in the hip adduction position will be a safe way to prevent patellofemoral pain syndrome resulting from abnormal patella lateral tracking.

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Optimization of Multiple Tower Cranes and Material Stockyards Layout (다중 양중장비와 자재 야적 위치의 최적 결정을 위한 모델 개발)

  • Kim, Kyong-Ju;Kim, Kyoung-Min;Lee, Sang-Kyu
    • Korean Journal of Construction Engineering and Management
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    • v.10 no.6
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    • pp.127-134
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    • 2009
  • This study aims to provide an optimal model for the layout of multiple tower cranes and material stockyards which have multiple candidate positions. In a high-rise building construction, the positional allocation of tower cranes and material stockyard has an effect on the travel time of material hauling. In addition, in case of using multiple tower cranes, specific location of a tower crane allocated to each material determines the efficiency of the works. Current optimal model limited to the optimization of position of single tower crane and material stockyards. This study suggests optimal model both for the positions of multiple tower cranes and material stockyards. Layout of multiple tower cranes requires additional allocation of each crane to each material hauling and control on the minimum distance between tower cranes. This optimization model utilizes genetic algorithm to deal with complex interaction on the candidate positions of multiple tower cranes, material stockyards, and types of materials. In order to identify its utility, case study was performed.

Rapid Soil Quality Assessment for Sustainable Agricultural Systems at Songco, Lantapan, Bukidnon, Philippines

  • Daquiado, Nonilona P.
    • 한국환경농학회:학술대회논문집
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    • 2011.07a
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    • pp.177-187
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    • 2011
  • This study was conducted to determine some physical and chemical properties of the soil and their relationship to spectroscopic-based (visible range) analytical methods while evaluating soil organic matter fractions and soil quality in degraded and non-degraded soils in a wide range of environments. Soil samples were collected from the different landscape positions of cultivated and noncultivated soils, and the latter from the same landscape positions but with different vegetation, at Songco, Lantapan, Bukidnon. The physical and chemical properties of the soils were determined at the SPAL, CMU, Musuan, Bukidnon while the metagenomic properties were determined at the Laboratory of the University of Missourri, Missourri, USA. Bulk density and air dry soil strength values of the soils from the cultivated areas were generally higher than those of the uncultivated areas. Also, soils at the summit generally had lower bulk density and soil strength values than the other landscape positions. Moreover, soils planted to camote (Ipomoea batatas) had higher bulk density and soil strength values compared to soils grown to pepper under the trees. Exchangeable calcium (Ca), magnesium (Mg), and potassium (K) and cation exchange capacity (CEC) of the soils were generally higher in uncultivated areas than those of the cultivated areas. A similar trend was observed for the potassium permanganate ($KMnO_4$)-oxidizable organic C contents determined by spectroscopic method and the total C contents determined by the Walkley-Black method. The $KMnO_4$-oxidizable organic C contents determined by spectroscopic method and the total C contents determined by the Walkley-Black method were closely related ($r=0.631^{**}$). Hence, the former method shows promise in assessing soil quality as it is a rapid test, relatively low cost and can be distributed as a field kit either with a portable spectrometer or with a color chart.

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A Landmark Based Localization System using a Kinect Sensor (키넥트 센서를 이용한 인공표식 기반의 위치결정 시스템)

  • Park, Kwiwoo;Chae, JeongGeun;Moon, Sang-Ho;Park, Chansik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.1
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    • pp.99-107
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    • 2014
  • In this paper, a landmark based localization system using a Kinect sensor is proposed and evaluated with the implemented system for precise and autonomous navigation of low cost robots. The proposed localization method finds the positions of landmark on the image plane and the depth value using color and depth images. The coordinates transforms are defined using the depth value. Using coordinate transformation, the position in the image plane is transformed to the position in the body frame. The ranges between the landmarks and the Kinect sensor are the norm of the landmark positions in body frame. The Kinect sensor position is computed using the tri-lateral whose inputs are the ranges and the known landmark positions. In addition, a new matching method using the pin hole model is proposed to reduce the mismatch between depth and color images. Furthermore, a height error compensation method using the relationship between the body frame and real world coordinates is proposed to reduce the effect of wrong leveling. The error analysis are also given to find out the effect of focal length, principal point and depth value to the range. The experiments using 2D bar code with the implemented system show that the position with less than 3cm error is obtained in enclosed space($3,500mm{\times}3,000mm{\times}2,500mm$).

Genetic Parameters for Some Leaf Characters in Flue-Cured Tobacco (Nicotiana tabacum L. ) at Two Representative Stalk Positions (황색종 연초(Nicotiana tabacum L.)의 엽위별 엽형질에 대한 유전자 효과분석)

  • 조수헌
    • Journal of the Korean Society of Tobacco Science
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    • v.10 no.2
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    • pp.117-122
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    • 1988
  • This experiment was conducted to study the nature of gene effects for the leaf characters in flue-cured tobacco. The genetic populations were derived from crosses between NC 2326 and Mc Nair 373, and NC 628 and DG-72. The generation means experiment Included the Pl, P2. Fl, F2, Bl and B2, which were frown at Taegu Experiment Station, Korea Ginseng & Tobacco Research Institute in 1984. Seedlings were transplanted to the field in a randomized block design with 3 replications. In each block, parental and Fl Plots contained 15 plants in a single row, F2, Bl and B2 plots being composed of 75 plant, in 5 rows. Leaf characters were measured of largest (middle leaf) and 5th leaf(top leaf) from the top after topping. Measurements of the length and width of leaf were obtained from the fresh the middle and top leaves, and weight of leaf, weight and width of midrib were from the satrap leaf after curing. Estimates of additive and dominance genetic variance were analyzed according to Gamble's biometrical model. The results obtained are as follows: 1. The additive gene effects were significant and larger than the dominance gene effects for all leaf and midrib characters in both stalk positions. 2. The dominance gene effects were significant for the length and width of leaf, and weight of midrib in the middle leaves. 3. The digenic epistatic effects were significant for the length and width of leaf in both stalk positions. 4. The additive gene effects were larger in the top than in the middle leaves and midrib characters.

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A Study on the Effects of Position Change on the Liver Shape on Radioisotope Scan (간(肝)스캔상(上) 체위변동(體位變動)에 따른 간형태(肝形態) 변화(變化)에 대(對)한 고찰(考察))

  • Hong, Kee-Suk;Choi, Du-Hyok;Yang, Young-Tae;Koh, Chang-Soon
    • The Korean Journal of Nuclear Medicine
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    • v.16 no.1
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    • pp.49-54
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    • 1982
  • For this study, the authors obtained and examined anterior views of the liver and spleen in two different positions, upright and supine, of 39 normal subjects and 20 patients with hepaticpathology by means of $^{99m}Tc-colloid$ and gamma camera. This examination confirms the following findings. In general, it is shown, left lobe of the liver in upright position becomes longer in height than in supine position, while the distance between lateral margin of the liver and that of the spleen becomes father in with in supine position than in upright position. The upper margin of liver moves more downward in upright position than in supine. It is noticeable that as for 5 cases with severe chronic liver disease, there is minimal alteration of the liver shape between in two positions. The comparison of the both positions for the better liver scan shows the following finding. Prominent caudate and/or left lobe are marked in the upright position in 16 cases out of the total 59, while none is found in the supine. The false cold area in lower part of the liver disappears in 7 cases in the upright position, while only one shows the disappeance of the false cold area in the supine. Left liver margin due to close contact of spleen is blurred in 3 cases in the upright position. In total 23 cases out of 59 support that the upright position is better for the liver scan, while only 4 cases support the supine position is better. These findings support two assumptions. One is that upright view can bo expected more improved resoluton than supine view for liver scan. Second is that minimal change of the liver shape in both views indicate the serious abnormality in the liver.

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