• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.1
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• pp.60-65
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• 2000

The virtual mass of net is an important parameter in the analysis and control of net movement in the water. This experiment was performed with the purpose of getting a relation on the quantity of netting and virtual mass of trawl nets using the circulating water channel that can control flow speed. Twelve types of conical nets were examined. Resistance of the conical net at the steady and acceleration state was recorded as text on the personal computer through the tension meter and current meter. The results were obtained as follows ;1. Resistance(R) of the conical net is proportional to the degree of attack angle in the sam e amount of twine material.2. Coefficient of the resistance(Cd)could be defined by the following regression model as a function of Reynolds Number(Re). Cd=0.039Re-0.14743. Resistance(R) is proportional to TSA(Twine surface area) and defined as follows; R=21.398TSA-0.12194. Coefficient of virtual mass(CM) could be calculated by the following first order regression model. CM=37.557U-8.96845. Virtual mass is directly proportional to Volume of net(V) or d/l.

• The Journal of Korean Physical Therapy
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• v.30 no.2
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• pp.73-77
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• 2018

Purpose: The prefrontal lobe, supplementary motor area, cerebellum, and basal ganglia are activated during gait. In addition, gait is controlled by nerves, such as the corticospinal tract (CST) and corticoreticular pathway (CRP). In this study, the presence of an injury to the CST and CRP was identified by diffusion tensor imaging and the characteristics of the gait pattern were investigated according to inferior cerebral artery infarction. Methods: One patient and six control subjects of a similar age participated. A 69-year-old female patient had an injury to the left basal ganglia, insular gyrus, corona radiata, dorsolateral prefrontal cortex, and postcentral gyrus due to an inferior cerebral artery infarction. Diffusion tensor imaging (DTI) data was acquired 4 weeks after the stroke. The kinematic and spatio-temporal parameters of gait were collected using a three-dimensional gait analysis system. Results: On 4 weeks DTI, the CST and CRP in the affected hemisphere did not show injury to the affected and unaffected hemisphere. Gait analysis showed that the cadence of spatio-temporal parameter was decreased significantly in the patient. The angle of the knee joint was decreased significantly in the affected and unaffected sides compared to the control group. Conclusion: The results of diffusion tensor imaging showed that although the patient was evaluated to be capable of an independent gait, the quality and quantity of gait might be reduced. This study could help better understand the gait ability analysis of stroke patients and the abnormal gait pattern of patients with a brain injury.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.868-874
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• 2015

Thrust variation is an essential parameter in a space mission such as landing on an atmosphereless planet or docking a spacecraft. In order to achieve the thrust variation control, using throttleable injector is a representative and general method. A dual-manifold injector, one of throttleable injectors, was used to control mass flow rate. Five kinds of injectors were designed and investigated in order to compare the spray characteristics of the dual-manifold injector with various tangential entries. Spray angles and patterns were measured to determine external flow characteristics and film thicknesses were measured in order to investigate the internal flow patterns.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.424-432
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• 2011

Shape parameters and design variables for a centrifugal compressor impeller were investigated for optimizing a centrifugal compressor. In order to compare the performance of an optimized impeller with the performance of the original impeller, an already tested impeller was chosen and design variables for optimization were selected. The meridional shapes at the shroud and at the hub were re-designed using the Bezier curve. The camber-lines of the impeller blade at the hub and at the tip were also expressed by the Bezier curve. The shape curves for impeller could be expressed using 6-8 control points. Among them, eight control points which have strong effect to the shape can be selected as design variables for optimization. Therefore, any impeller which is expressed by data points for its shape can be optimized using few design variables.

• Journal of KIISE:Databases
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• v.34 no.5
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• pp.379-388
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• 2007

Disordered streams may cause inaccurate or delayed results in window-based queries. Existing approaches usually leverage buffers to hand]e the streams. However, most of the approaches estimate the buffer size simply based on the maximum network delay in the streams, which tends to over-estimate the buffer size and result in high latency. In this paper, we propose a probabilistic approach to estimate the buffer size adaptively according to the fluctuated network delays. We first assume that intervals of tuple generations follow an exponential distribution and network delays have a normal distribution. Then, we derive an estimation function from the assumptions. The function takes a drop ratio as an input parameter, which denotes a percentage of tuple drops permissible during query execution. By describing the drop ratio in a query specification, users can control the quality of query results such as accuracy or latency according to application requirements. Our experimental results show that the proposed function has better adaptivity than the existing function based on the maximum network delay.

• KSBB Journal
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• v.18 no.3
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• pp.197-201
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• 2003

Automatic addition of glucose, ammonium and phosphate to alcohol distillery wastewater and their control at low concentrations have been carried increase the cell concentration of a baker's yeast cultivated in the wastewater. Glucose was automatically added using dissolved oxygen as the control parameter, and maintained below 300 mg/L. Ammonium was automatically added by a pH-stat method and maintained in the low range of 12.6~17.4 mM. An automated FIA system, which used an ascorbic acid-based method was developed for the automatic analysis nad addition of phosphate. With this system, the phosphate concentration was succesfully analysed and controlled afrer 19.4 hr in the range 23.3~43.4 mg/L. The cell concentration was increased by 33.0-fold by the addition of these three nutrients. The overall specific growth rate of the yeast was 0.19 $hr^{-1}$.

• The Journal of Advanced Prosthodontics
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• v.4 no.1
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• pp.18-23
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• 2012

PURPOSE. The purpose of this prospective study was to evaluate the effect of early loading on survival rate or clinical parameter of anodic oxidized implants during the 12- month postloading period. MATERIALS AND METHODS. Total 69 implants were placed in 42 patients. Anodic oxidized implants (GS II, Osstem Cor., Busan, Korea) placed on the posterior mandibles were divided into two groups, according to their prosthetic loading times: test group (2 to 6 weeks), and control group (3 to 4 months). The implant survival rates were determined during oneyear postloading period and analyzed by Kaplan-Meier method. The radiographic peri-implant bone loss and periodontal parameters were also evaluated and statistically analyzed by unpaired t-test. RESULTS. Total 69 implants were placed in 42 patients. The cumulative postloading implant survival rates were 88.89% in test group, compared to 100% in control group (P<.05). Periimplant marginal bone loss (T: $0.27{\pm}0.54$ mm, C: $0.40{\pm}0.55$ mm) and periodontal parameters showed no significant difference between the groups (P>.05). CONCLUSION. Within the limitation of the present study, implant survival was affected by early loading on the anodic oxidized implants placed on posterior mandibles during one-year follow-up. Early implant loading did not influence peri-implant marginal bone loss, and periodontal parameters.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.129-138
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• 2009

Purpose: This study was designed to compare the bond regeneratiom effects of treatment using silk fibroin membrane ( Nanogide-S$^{(R)}$ ) resorbable barrier with control group treated by polyactic acid / polylacticglycolic acid membrane(Biomesh$^{(R)}$ ) Methods: 44 severe bone loss on extraction socket from 44 patients were used in this study. In experimental group 22 sites of them were treated by silk fibrin membrane as and the other 22 sites were treated by polyactic acid/ polylacticglycolic acid membrane as a control group. Clinical parameters including recovered bone width, length and radiographic parameter of vertical length were evlauated at base line and 3 months after surgery. Results: 1) Severe bone width, length was significantlly decreased in two group. 2) Bone width, length was significantlly decreased in two group. 3) Decreased bone width, length and radiographic examination differences between group. Conclusions: On the basis of these results, silk fibrin resorbable membrane has similar bone regeneration ability to polyactic acid / polylacticglycolic acid membrane in guided bone regeneration for severe bone loss defect on extraction socket.

• The Journal of Advanced Prosthodontics
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• v.11 no.6
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• pp.331-340
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• 2019

PURPOSE. The purpose of this study is to assess the accuracy of three intraoral scanners along the complete dental arch and evaluate the feasibility of the assessment methodology for further in vivo analysis. MATERIALS AND METHODS. A specific measurement pattern was fabricated and measured using a coordinate measuring machine for the assessment of control distances and angles. Afterwards, the pattern was placed and fixed in replica of an upper jaw for their subsequent scans (10 times) using 3 intraoral scanners, namely iTero Element1, Trios 3, and True Definition. 4 reference distances and 5 angles were measured and compared with the controls. Trueness and precision were assessed for each IOS: trueness, as the deviation of the measures from the control ones, while precision, as the dispersion of measurements in each reference parameter. These measurements were carried out using software for analyzing 3-dimensional data. Data analysis software was used for statistical and measurements analysis (α=.05). RESULTS. Significant differences (P<.05) were found depending on the intraoral scanner used. Best trueness values were achieved with iTero Element1 (mean from 10 ± 7 ㎛ to 91 ± 63 ㎛) while the worst values were obtained with Trios3 (mean from 42 ± 23 ㎛ to 174 ± 77 ㎛). Trueness analysis in angle measurements, as well as precision analysis, did not show conclusive results. CONCLUSION. iTero Element1 was more accurate than the current versions of Trios3 and True Definition. Importantly, the proposed methodology is considered reliable for analyzing accuracy in any dental arch length and valid for assessing both trueness and precision in an in vivo study.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.816-822
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• 2003

In this paper, we propose an efficient iteration control method with low complexity for Turbo TCM(Turbo Trellis Coded Modulation) decoding which will be used fur power-limited environment. As the decoding approaches the performance limit of a given turbo code, any further iteration results in very little improvement. Therefore, it is important to devise an efficient criterion to stop the iteration process and prevent unnecessary computations and decoding delay. This paper presents an efficient algorithm for turbo TCM decoding that can greatly reduce the delay and iteration number. The proposed method use adaptive iteration number according to the criterion using the extrinsic information variance parameter in turbo TCM decoding process. The simulation results show that the proposed technique effectively can reduce the decoding delay and computation with very little performance degradation.