• Progress in Medical Physics
• /
• v.10 no.2
• /
• pp.63-71
• /
• 1999

For the purpose of utilization in 3-D conformal radiotherapy and whole body radiosurgery, the Whole Body 3-Dimensional Topographic Radiation Therapy System has been developed. Whole body frame was constructed in order to be installed on the couch. Radiopaque catheters were engraved on it for the dedicated coordinate system and a MeV-Green immobilizer was used for the patient setup by the help of side panels and plastic rods. By designing and constructing the whole body frame in this way, geometrical limitation to the gantry rotation in 3-D conformal radiotherapy could be minimized and problem which radiation transmission may be altered in particular incident angles was solved. By analyzing CT images containing information of patient setup with respect to the whole body frame, localization and coordination of the target is performed so that patient setup error may be eliminated between simulation and treatment. For the verification of setup, the change of patient positioning is detected and adjusted in order to minimize the setup error by means of comparison of the body outlines using 3 CCTV cameras. To enhance efficiency of treatment procedure, this work can be done in real time by watching the change of patient setup through the monitor. The method of image subtraction in IDL (Interactive Data Language) was used to visualize the change of patient setup. Rotating X-ray system was constructed for detecting target movement due to internal organ motion. Landmark screws were implanted either on the bones around target or inside target, and variation of target location with respect to markers may be visualized in order to minimize internal setup error through the anterior and the lateral image information taken from rotating X-ray system. For CT simulation, simulation software was developed using IDL on GUI(Graphic User Interface) basis for PC and includes functions of graphic handling, editing and data acquisition of images of internal organs as well as target for the preparation of treatment planning.

• The Korean Journal of Nuclear Medicine
• /
• v.39 no.6
• /
• pp.445-455
• /
• 2005

Purpose: We developed an animal SPECT system using clinical Philips ARGUS scintillation camera and pinhole collimator with specially manufactured small apertures. In this study, we evaluated the physical characteristics of this system and biological feasibility for animal experiments. Materials and Methods: Rotating station for small animals using a step motor and operating software were developed. Pinhole inserts with small apertures (diameter of 0.5, 1.0, and 2.0 mm) were manufactured and physical parameters including planar spatial resolution and sensitivity and reconstructed resolution were measured for some apertures. In order to measure the size of the usable field of view according to the distance from the focal point, manufactured multiple line sources separated with the same distance were scanned and numbers of lines within the field of view were counted. Using a Tc-99m line source with 0.5 mm diameter and 12 mm length placed in the exact center of field of view, planar spatial resolution according to the distance was measured. Calibration factor to obtain FWHM values in 'mm' unit was calculated from the planar image of two separated line sources. Te-99m point source with i mm diameter was used for the measurement of system sensitivity. In addition, SPECT data of micro phantom with cold and hot line inserts and rat brain after intravenous injection of [I-123]FP-CIT were acquired and reconstructed using filtered back protection reconstruction algorithm for pinhole collimator. Results: Size of usable field of view was proportional to the distance from the focal point and their relationship could be fitted into a linear equation (y=1.4x+0.5, x: distance). System sensitivity and planar spatial resolution at 3 cm measured using 1.0 mm aperture was 71 cps/MBq and 1.24 mm, respectively. In the SPECT image of rat brain with [I-123]FP-CIT acquired using 1.0 mm aperture, the distribution of dopamine transporter in the striatum was well identified in each hemisphere. Conclusion: We verified that this new animal SPECT system with the Phlilps ARGUS scanner and small apertures had sufficient performance for small animal imaging.

• The KIPS Transactions:PartA
• /
• v.11A no.7 s.91
• /
• pp.555-562
• /
• 2004

Both global volume reduction and local shape changes of hippocampus within the brain indicate their abnormal neurological states. Hippocampal shape analysis consists of two main steps. First, construct a hippocampal shape representation model ; second, compute a shape similarity from this representation. This paper proposes a novel method for the analysis of hippocampal shape using integrated Octree-based representation, containing meshes, voxels, and skeletons. First of all, we create multi-level meshes by applying the Marching Cube algorithm to the hippocampal region segmented from MR images. This model is converted to intermediate binary voxel representation. And we extract the 3D skeleton from these voxels using the slice-based skeletonization method. Then, in order to acquire multiresolutional shape representation, we store hierarchically the meshes, voxels, skeletons comprised in nodes of the Octree, and we extract the sample meshes using the ray-tracing based mesh sampling technique. Finally, as a similarity measure between the shapes, we compute $L_2$ Norm and Hausdorff distance for each sam-pled mesh pair by shooting the rays fired from the extracted skeleton. As we use a mouse picking interface for analyzing a local shape inter-actively, we provide an interaction and multiresolution based analysis for the local shape changes. In this paper, our experiment shows that our approach is robust to the rotation and the scale, especially effective to discriminate the changes between local shapes of hippocampus and more-over to increase the speed of analysis without degrading accuracy by using a hierarchical level-of-detail approach.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.9
• /
• pp.717-722
• /
• 2001

This paper presents a methodology on the backward path tracking control of a trailer type robot which consists of two parts: a tractor and a trailer. It is difficult to control the motion of a trailer vehicle since its dynamics is non-holonomic. Therefore, in this paper, the modeling and parameter estimation of the system using a real-coded genetic algorithm(RCGA) is proposed and a backward path tracking control algorithm is then obtained based on the linearized model. Experimental results verify the effectiveness of the proposed method.

• Korean Journal of Cognitive Science
• /
• v.3 no.1
• /
• pp.61-78
• /
• 1991

This paper descibes the study of application of a modified Neocognitron model with backward path for the recognition of Hangul(Korean) syllabic characters. In this original report, Fukushima demonstrated that Neocognitron can recognize hand written numerical characters of $19{\times}19$ size. This version accepts $61{\times}61$ images of handwritten Hangul syllabic characters or a part thereof with a mouse or with a scanner. It consists of an input layer and 3 pairs of Uc layers. The last Uc layer of this version, recognition layer, consists of 24 planes of $5{\times}5$ cells which tell us the identity of a grapheme receiving attention at one time and its relative position in the input layer respectively. It has been trained 10 simple vowel graphemes and 14 simple consonant graphemes and their spatial features. Some patterns which are not easily trained have been trained more extrensively. The trained nerwork which can classify indivisual graphemes with possible deformation, noise, size variance, transformation or retation wre then used to recongnize Korean syllabic characters using its selective attention mechanism for image segmentation task within a syllabic characters. On initial sample tests on input characters our model could recognize correctly up to 79%of the various test patterns of handwritten Korean syllabic charactes. The results of this study indeed show Neocognitron as a powerful model to reconginze deformed handwritten charavters with big size characters set via segmenting its input images as recognizable parts. The same approach may be applied to the recogition of chinese characters, which are much complex both in its structures and its graphemes. But processing time appears to be the bottleneck before it can be implemented. Special hardware such as neural chip appear to be an essestial prerquisite for the practical use of the model. Further work is required before enabling the model to recognize Korean syllabic characters consisting of complex vowels and complex consonants. Correct recognition of the neighboring area between two simple graphemes would become more critical for this task.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.2
• /
• pp.129-136
• /
• 2000

Differentiation and development of the digestive organ of the black sea bream, AcanHepagus schlegeli were studied by means of histological methods. The hatched lawn if TL(total length) $2.0 mm (n=10)$ had a yolk sac of $1,000{\times}590 {\mu}m$ and simple straight digestive tract, which was composed of cuboidal epithelium. In the pre-larval stage of TL $3.5 mm$, digestive tract could be distinguished into esophagus, stomach and intestine, and the exocrine glands were appeared in the pancreas. In this stage mucosal folds, eosinophilic granule cells and brush border were observed in the posterior intestine. Yolky materials were completely absorbed and the brush border was recognized in the free surface of anterior intestine in TL $3.7 mm$. In the stomach mucosal folds began to appear from TL $4.0 mm$. In this time the zymogen granules were recognized in the cytoplasm of pancreatic exocrine cells. In the post-larval stage ranged from $4.5 to 5.0 mm$ in TL, hepatic cords started to develop, and the mucous secretory cells of PAS positivewere observed at esophagus and intestine. In the post-larval stage ranged from $6.3 to 7.0 mm$ in TL, histological layer of esophagus and intestine could be distinguished into serous membrane, muscular layer, submucosal layer and mucosal layer. From over TL $9.0 mm$, stomach could be distinguished into cardiac, fundic and pyloric portion, and the gastric gland began to appear at mucosal fold of fundic stomach. In the juvenile stage ranged from $10.0 to 11.0 mm$ in TL, histological structures of esophagus and intestine were similar to those of adult. From over TL $15.0 mm$, histological structures of stomach were similar to those of adult. Structural and functional digestive organ of black sea bream was present from the juvenile stage ranged from $15.0 to 17.0 mm$ in TL.

• Journal of Korean Orthopaedic Sports Medicine
• /
• v.8 no.2
• /
• pp.102-108
• /
• 2009

Purpose: The purpose of this study is to report a result of the technique that reconstruct posterior cruciate ligament (PCL) and posterolateral corner (PLC) simultaneously using a fresh-frozen Achilles tendon allograft. Materials and Methods: Forty two patients (45 legs) underwent PCL and PLC reconstruction were included. There were 38 males and 4 females. Mean age was 39 years. Used graft was a fresh frozen Achilles tendon allograft, which was divided by two size, larger one (${\emptyset}$ 10 mm) for PCL reconstruction and smaller one (${\emptyset}$ 8 mm) for PLC reconstruction. Arthroscopic reconstruction of the PCL was performed using transtibial, single incision, and single bundle technique with 10mm fresh frozen Achilles allograft tendon first. After PCL reconstruction, reconstruction procedure for posterolateral instability was performed using modified figure of "8" technique using smaller gtaft. For clinical evaluation, range of motion, posterior drawer test, varus stress test, prone external rotation (dial) test, Lysholm score, Tegner activity scale and posterior stress radiograph were used. Mean follow up period was 25 months. Results: Preoperatively posterior drawer test was 5 cases in grade II and 40 cases in grade III posterior instability. At final follow-up 22 cases returned within normal condition, 18 cases grade I and 5 cases grade II posterior instability. Though all patients showed positive result over 10 degrees in dial and varus stress test preoperatively, but only 9 cases showed positive both test at final follow-up. The range of motion deficit over $10^{\circ}$ flexion was 3 cases. Lysholm score was improved from mean 50 preoperatively to mean 83(p<0.05) and Tegner activity scale improved from mean 2.1 preoperatively to mean 4.6(p<0.05). In posterior stress radiographs, posterior displacement was improve from mean 16mm preoperatively to 4.1mm after treatment(p<0.05). All patients had improved compared to their pre-operative status as measured by physical examination such as posterior drawer test, varus stress test, dial test. Conclusion: We had successful results by combined reconstruction of the PCL & PLC with a fresh frozen Achilles tendon allograft in patients with PCL and posterolateral rotatory instability at a time.

• Journal of the Korean Arthroscopy Society
• /
• v.8 no.1
• /
• pp.14-18
• /
• 2004

Purpose: To compare the mid-term follow-up results of anterior cruciate ligament(ACL) reconstruction with the bone-patellar tendon- bone(BTB) autograft to those with the BTB allograft. Materials and Methods: Retrospective study was performed in 59 cases with BTB autograft and 42 cases with BTB allograft. Evaluations include Lysholm score, 2000 IKDC subjective knee score, Shelbourne patello-femoral pain score , Lachman test, pivot shift test, KT-1000 arthrometer test and 2000 IKDC knee examination. Results: There were no significant statistic differences between two groups in Lysholm score and 2000 IKDC subjective knee score of more than 70 (p<0.05). Five cases(8.5%) showed the patello-femoral pain score less than 80 according to Shelboume with autograft group and two cases(4.8%) with allograft group (p<0.05). Lachman test, pivot shift test and KT-1000 arthrometer test showed no significant statistic differences between two groups(P<0.05). Fifty-four cases(91.5%) were normal or nearly normal according to the 2000 IKDC knee examination with autograft group and thirty-eight cases(90.4%) with allograft group(p<0.05).Conclusion: BTB allograft as well as BTB autograft is considered to be an acceptable choice for ACL reconstruction.

• The Korean Journal of Pesticide Science
• /
• v.21 no.1
• /
• pp.9-16
• /
• 2017

A survey was conducted to research on planting system and pesticide spray methods including spray volume, sprayer types, and spray nozzles used in apple orchards. The survey was deployed to 395 farmers in 17 cities and towns including 7 regions which are major producers of apple via interview. Major apple varieties were Fuji (79.2%) and Hongro (50.9%) and high density planting system was mainly used in apple orchards (distance between rows: 4.0-4.5 m (73.1%); planting distance: 1.5-3.5 m (88.6%); canopy height: 3.0-4.5 m (88.2%)). The percentages of sprayer types were 77.6% and 22.1% for speed sprayer (airblast sprayer) and power sprayer, respectively. Spray volumes per 10a were 250-300 L in April, the month of spraying the lowest volume, and 300-400 L in June-August, the months of spraying the highest volume. Significant difference in spray volumes were not observed between conventional planting and high density planting, but regional spray volume showed significant difference. The main nozzles used by apple farmers using power sprayers were super jet nozzle (45%), super wide nozzle (26%), and 2-3 vertical head nozzle (25%). The results will helpful to establish practical agrochemicals management policy including suggestion of pesticide spray volume and evaluation of pesticide residue data and efficacy data.

• Journal of the Korean Arthroscopy Society
• /
• v.12 no.1
• /
• pp.18-23
• /
• 2008

Purpose: The purpose of this study is to evaluate the clinical results of the function and stability of ACL reconstruction using the flexible reamer. Materials and Methods: We reviewed 98 patients who taken ACL reconstruction using the flexible reamer from March, 1999 to May, 2004. And the follow-up period was more than 12 months in all cases. We used the subjective tests including Lysholm knee score and 2000 International Knee Documentation Committee(IKDC) subjective knee score, and the objective tests such as anterior drawer test, Lachman test, pivot shift test, and KT-2000 arthrometer to evaluate the clinical results. Results: In the range of motion of the affected knee, the extension deficit more than 5 degree was 8 cases preoperatively and 1 case postoperatively. The flexion deficit more than 5 degree was 12 cases preoperatively and 2 cases postoperatively. The mean Lysholm knee score was 61.3 point(${\pm}3.5$ SD) preoperatively and 87.7 point(${\pm}2.0$ SD) postoperatively. The mean 2000 International Knee Documentation Committee(IKDC) subjective knee score was 49 point(${\pm}3.3$ SD) preoperatively and 84 point (${\pm}2.2$ SD) postoperatively. 93 cases were more than grade II in Lachman test preoperatively and 5 cases postoperatively. 71 cases were more than grade II in pivot shift test preoperatively but 89 cases were negative postoperatively. The mean maximal manual difference by KT-2000 arthrometer was 6.8 mm(${\pm}1.9$ SD) preoperatively and 1.8 mm(${\pm}0.8$ SD) postoperatively. Conclusion: ACL reconstruction using the flexible reamer achieved the ideal isometric point of femur and anatomic graft placement, so we could obtain good results, especially in rotational stability.