• The Journal of Korean Orthopaedic Ultrasound Society
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• v.3 no.1
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• pp.8-14
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• 2010

Purpose: We wished to evaluate the clinical usefulness of ultrasound, when loose body is palpated and is shown radiographically in knee. Material and Methods: Twenty-five knees of twenty-two patients with loose body in knee radiographically from March, 2007 to July, 2009 were involved in this study, there were 8 males and 14 females, there were 11 right knees, 8 left knees and 3 both knees, the average age was 56.3 years (range, 32~76 years). The location of loose bodies were 13 cases at suprapatella pouch, 1 case at infrapatella anterior compartment and 11 cases at posterior compartment. In loose bodies of suprapatella pouch, we examined the mobility of loose bodies longitudinally with ultrasound placed at superior patella pole while flexing and extending the knee. In loose bodies of infrapatella anterior and posterior compartment, we examined the mobility of loose bodies longitudinally and transversely with ultrasound while flexing and extending the knee. Results: All cases of suprapatella pouch and infrapatella anterior compartment were diagnosed to movable loose bodies and were removed surgically, all cases of posterior compartment were diagnosed to immovable loose bodies and were not removed. Conclusion: When we determined the surgical removal according to mobility of loose body in knee, ultrasound may be helpful clinically.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.5
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• pp.46-56
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• 2013

This research prepared safety standard for out-door fitness and this research's purpose is to evaluate and investigate safety condition for out-door fitness which was distributed in domestic residence by applying TUV standard which evaluate product's safety inspection. We choose twelve companies which have many sales' amount and investigated for ten out-door fitness which have high consumer preferences. As a result of that, the ratio of successful applicants for safety evaluation was 55.1%. The terms desired was evaluated highly in safety for out-door fitness's fixing condition. However, the terms desired was evaluated lowly in safety for movable condition. Fitness equipment which has high consumer preferences was compared lowly than other equipment in safety part. It was analyzed that there was no difference in safety evaluation according to manufacturing company. So, it is necessary to prepare safety standard by establishing law in order to prevent accident while they are using because we cannot think that fitness equipments which was distributed in domestic area have high safety. We think that preparing safety standard can influence on preventing accident and reinforcing out-door fitness manufacturing companies' competitive.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.6
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• pp.6-11
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• 2010

Amount of power generated from solar photovoltaic can vary according to solar flux of sunlight due to nature of solar cell panel, and an angle that the sun and the surface of cell makes brings difference in amount of power generation. Solar flux is decided by location of surface of the Earth that is classified into longitude and latitude, but on the other hand, an angle that the sung and the surface of cell makes can be changed by changing the angle of a solar power generation device at the fixed location. A method of changing the angle of a solar power generation device as a measure for improving practical power generation efficiency. and studies about a solar tracking device for this are in active. This study conducted a research on a solar tracking system for improvement of solar power generation efficiency. A solar tracking system of this study is composed of a sensor part to confirm a location of the sun with a semiconductor photosensor using the photo conductive effect, and it analyzed output signal of a sensor by using microprocessor and it produced a control signal of driving part for tracking the sun. A solar power generator (25W) was produced to analyze performance of a solar tracking system and usefulness of a solar tracking device that was designed and produced in this study was confirmed through experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1365-1373
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• 2002

In this paper, we present two types of vision algorithm that mobile robot has CCD camera. for obstacle avoidance. This is simple algorithm that compare with grey level from input images. Also, The mobile robot depend on image processing and move command from PC host. we has been studied self controlled mobile robot system with CCD camera. This system consists of digital signal processor, step motor, RF module and CCD camera. we used wireless RF module for movable command transmitting between robot and host PC. This robot go straight until recognize obstacle from input image that preprocessed by edge detection, converting, thresholding. And it could avoid the obstacle when recognize obstacle by line histogram intensity. Host PC measurement wave from various line histogram each 20 pixel. This histogram is (x, y) value of pixel. For example, first line histogram intensity wave from (0, 0) to (0, 197) and last wave from (280, 0) to (2n, 197. So we find uniform wave region and nonuniform wave region. The period of uniform wave is obstacle region. we guess that algorithm is very useful about moving robot for obstacle avoidance.

• The Journal of the Korean bone and joint tumor society
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• v.9 no.2
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• pp.233-237
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• 2003

Calcifying aponeurotic fibroma is a benign, aggressive fibrous tumor seen in childhood or adolescence that most commonly affects the palm. We report our experience in treating calcifying aponeurotic fibroma in the hand of fifteen-year-old boy. He was presented with a recurrent mass in hypothenar area of his left hand. He had a history of local excision of the mass 7 years ago in local clinic. The palpable mass was hard, tender and movable. The simple X-ray revealed multifocally scattered microcalcifications in the mass. The excised mass showed the features of dense fibrotic soft tissue tumor with multiple small whitish calcifications. The microscopic sections showed a lobulated and a poorly circumscribed proliferation of dense fibrous tissue, containing islands of metaplastic chondroid differentiation with prominent calcification. The recommended treatment of this lesion is wide excision allowing for sparing of functional or vital structures, but high recurrence rate as this case has been reported to be more than 50 percent.

• Fire Science and Engineering
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• v.15 no.1
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• pp.100-107
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• 2001

A Interior material, a main cause of fire-growth and generating toxic gas when it burns, should be dealt with great care in life safety design. Nonetheless, it has been used recklessly with undue attention to its contribution to fire in particular in entertainment occupancy and causes many victims in fire. Therefore, this study attempts to examine the current use of interior material in Korea and find out what to be improved and enhanced in terms of related regulations. Based on the comparison and analysis of the Korea regulation with those of advanced nations, suggestions are made for an effective and efficient improvement and complement to the current system. What can be suggested from this study are as follows. The use of interior material should be controlled under the unified regulation of fire-safety codes. Code should be set up so that the current construction enforcement should be applied in retroactive to those entertainment buildings that obtained a license prior to the implementation of the system certifying that the building is fire-resistant and fire-protective. The legislation should be made to control the fire-protection facilities of small-sized, underground entertainments. It should be obliged to present the blueprint displaying the use of interior material at the time of changing occupancy. Or, it should be compelled to report changes that go way without permit to the administrative office. A compulsory provision should be set up to have a fire-resistant performance to movable furniture. The classification index designating the fire hazard of interior material by flame spread rate and smoke toxicity and its test method should be established.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.76-87
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• 1998

The concentration of welding fume was measured by 221 welders themselves in chassis frame workplace of the manufactory from February, 1, 1996 to May, 31, 1997. Welding parameters were the welding current and the distance between helmet and arc. Those two optimum conditions were proposed by excess probability analysis using logistic regression, so the best position in the workplace was proposed considering two factors to control the welding fume. The results are as followings; 1) The excess proability of welding fume TLV was over 99% in above 260 Amperes of welding current and also in below 30cm of distanced between helmet and arc. 2) The equation from logistic regression analysis using SPSS/PC+5.02 had the welding current as a independent variable and the excess of welding fume TLV as a dependent variable (p<0.05). Logit(welding fume TLV) = 0.1296 ${\times}$ wlding currnet - 28.8750 3) The equation from logistic regression analysis using SPSS/PC+5.02 had the distance between helmet and arc as a independent variable and the excess of welding fume threshold limit value a, a dependent variable (p<0.05). Logit (welding fume TLV) = -0.6809 ${\times}$ distance between helmet and arc +25.1665 4) Considering both cases or 2) and 3). the result equation is following. (p<0.05). Logit (welding fume TLV) = 0.1346 ${\times}$ welding current -0.3859 ${\times}$ distance between helmet and arc -15.7382 5) The excess probability of welding fume threshold limit value was 100% in above 240 Ampere of welding current. Thus, below 220 Ampere can be suggested to reduce the 40% number of welders who have a excess welding fume threshold limit value. 6) The excess probability of welding fume TLV was 100% in below 34cm of distance between helmet and arc. Thus, over 38cm can be suggested to reduce the 33% number of welders who have a excess welding fume TLV. 7) Considering both 5) and 6) cases, first of all, the best welding current can be 200 Ampere to have a below 15% of welding fume excess probability for the welders who works in distance of 34-37cm. Secondly, to have a below 30% excess probability of welding fume TLV, the working distance must be over 38cm in 220 Ampere and 32cm in 200 Ampere. 8) To reduce the average exposure concentration of welding fume ($8.21{\pm}5.83mg/m^3$), the movable local exhaust system equipped with flexible hoods can be used.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.754-759
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• 2015

Nowadays, short distance communication systems with low power energy (LPE) are developed for identification and monitoring of site identification of vessel crews and passengers (SIVCP). LPE communication modules, such as Bluetooth low energy (BLE) and Zigbee, are used for short distance communications with LPE. These modules enable 1:N communications and their popularity is growing since the modules can be mounted on movable objects, such as mobile devices and human body. When these modules are used, the important factor that affects their operation time and design are the capacity and size of battery. Therefore, they must be made as small as possible, and the battery should be selected to be slightly smaller than the module. In this study, we calculate the theoretical life of batteries used in SIVCP BLE modules using data sheet and discharge characteristic graph under the condition of a 1/250 transmission-ratio (TR). We thus calculate experimental life by measuring transmission current for the same TR, and low speed mode current for a 1/5000 TR and measure long-term experimental life using 1/25 TR for days. Through these experiments, we verify experimental methods for the prediction and extension of battery life that would enable us to select appropriate sizes of batteries based on vessel usage and passenger types. The selections of the module TR and battery size are important factors affecting the cost reduction of module design, the battery maintenance, and passenger convenience.

• Journal of Korean Neurosurgical Society
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• v.53 no.5
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• pp.288-292
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• 2013

Objective : Vertebral distraction is routinely performed during anterior cervical discectomy and fusion (ACDF). Overdistraction can injure the facet joints and may cause postoperative neck pain consequently. The purpose of this study was to investigate the clinical relevance of distraction force during ACDF. Methods : This study included 24 consecutive patients with single level cervical disc disease undergoing single level ACDF. We measure the maximum torque just before the the arm of the Caspar retractor was suspended by the rachet mechanism by turning the lever on the movable arm using a torque meter. In order to turn the lever using the torque driver, we made a linear groove on the top of the lever. We compared the neck disability index (NDI) and visual analogue scale (VAS) scores between the high torque group (distraction force>6 $kgf{\cdot}cm$) and the low torque group (distraction force${\leq}6kgf{\cdot}cm$) at routine postoperative intervals of 1, 3, 5 days and 1, 3, 6 months. Results : The VAS scores for posterior neck pain had a linear correlation with torque at postoperative 1st and 3rd days ($y=0.99{\times}-1.1$, $r^2=0.82$; $y=0.77{\times}-0.63$, $r^2=0.73$, respectively). VAS scores for posterior neck pain were lower in the low torque group than in the high torque group on both 1 and 3 days postoperatively ($3.1{\pm}1.3$, $2.6{\pm}1.0$ compared with $6.0{\pm}0.6$, $4.9{\pm}0.8$, p<0.01). However, the difference in NDI scores was not statistically significant in all postoperative periods. Conclusion : Vertebral distraction may cause posterior neck pain in the immediate postoperative days. We recommend not to distract the intervertebral disc space excessively with a force of more than 6.0 $kgf{\cdot}cm$.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.429-434
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• 2004

In this paper, we designed a reconfigurable slot antenna using sequentially voltage-applied RF MEMS switches. In order to obtain pull-in voltage and maximum stress of the MEMS switches, the switch structures in accordance with airgap height was analyzed by ANSYS simulation A actuation voltage of MEMS switches can be determined by switch geometry and airgap height between a movable plate and a bottom plate. The designed lengths of MEMS switches were 240 $\mu\textrm{m}$, 320 $\mu\textrm{m}$, 400 $\mu\textrm{m}$, respectively and the airgap was 6$\mu\textrm{m}$. The total size of the designed slot antenna was 10 mm x 10 mm and the slot length and width were 500 $\mu\textrm{m}$ and 200 $\mu\textrm{m}$, respectively. The length and size of the CPW feedline were 5 mm and 30-80-30 $\mu\textrm{m}$, respectively. and then the size of the CPW in the slot was 50-300-150 $\mu\textrm{m}$. The tuning of the resonant frequency of the proposed device is realized by varying the electrical length of the antenna, which is controlled by applying the DC bias voltages to the RF MEMS switches. The designed slot antenna has been simulated, fabricated and measured.