• Journal of Yeungnam Medical Science
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• v.10 no.2
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• pp.400-408
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• 1993

During the period from March 1990 to November 1993, 22 children with diplaced supracondylar fracture of humerus were treated by closed reduction and percutaneous K-wire fixation at department of Orthopaedic surgery in Yeungnam University. All fracture were treated with closed reduction under the general anesthesia and percutaneous pinning. After the fracture was internally fixed, intraoperative anteroposterior reontgenograms of each distal humerus were compared. Only anatomical reduction ensured good result, because the main cause of late cubitus varus was medial tilting of distal fragment. We could follow up 10 patients more than one year. By Flynn's criteria, satisfactory result were obtained in 9 of the 10. Unsatisfactory one had a limitation in flexion of elbow joint, but had no problem in cosmetic feature. In short term follow up of 7 patients, 5 patients had a satisfactory result, too. There were no neurovascular complication and hospitalization was shortened to 11.4 days. Closed reduction and percutaneous pinning provided stabillity, vascular safety, simplified management, reduced hospital stay. This is safe and reliable technique for obtaining and maintaining an excellent reduction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.148-158
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• 2011

Stationary nodes and mobile nodes co-exist wireless sensor network(WSN) can provide variety of new services. The stationary sensor node acts not only the gathering the environmental sensing data but also a access point to bidirectional communication with numerous mobile sensor nodes(mobile node), and the mobile sensor nodes are installed inside mobile objects and identify the location in real-time and monitor the internal status of the object. However, only using the legacy WSN protocol, it is impossible to set up the stable network due to the several reasons caused by the free-mobility of the mobile nodes. In this paper, we suggest three methods to increase the hit-ratio of the asynchronous message delivery(AMD) among mobile nodes. We verified the performance of the suggested methods under the stationary-mobile co-existed WSN testbed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.37-44
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• 2009

A novel phase-locked loop(PLL) architecture with resistance and capacitance scaling scheme has been proposed. The proposed PLL has three charge pumps. The effective capacitance and resistance of the loop filter can be scaled up/down according to the locking status by controlling the direction and magnitude of each charge pump current. This architecture makes it possible to have a narrow bandwidth and low resistance in the loop filter, which improves phase noise and reference spur characteristics. It has been fabricated with a 3.3V $0.35{\mu}m$ CMOS process. The measured locking time is $25{\mu}s$ with the measured phase noise of -105.37 dBc/Hz @1MHz and the reference spur of -50dBc at 851.2MHz output frequency

• 한국노년학
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• v.36 no.4
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• pp.1109-1124
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• 2016

We examined the effect of stereotype threat (STT) on spatial working memory and facial emotion recognition in Korean elderly. In addition, we investigated the role of expected moderator such as self-perception of aging. Seventeen seniors (male=7) received basic cognitive tests including K-WMS-IV, MMSE and answered self-report questionnaires including self-perception of aging, anxiety of aging, attitude toward aging and age identity on the first visit. On the second visit, they were exposed to negative stereotype by reading a script detailing cognitive decline related to aging while a control group was exposed to a neutral content. Following the exposure, they were tested on a spatial-working memory task (Corsi-block tapping task) and emotion recognition task (facial expression identification task). The results showed that the seniors exposed to STT showed significantly lower performance on emotion recognition task (p < .05) (i.e., especially on the more difficult facial stimuli). In addition, there was a significant interaction between STT and self-perception of aging (p< .05), indicating that those who have positive self-perception of aging did not show impairment in emotion recognition task and difficult spatial working memory task under STT. On the other hand, those with negative self-perception of aging showed impaired performance under STT. Taken together, the current study suggests that being exposed to STT could negatively influence cognitive and emotional functioning of elderly. Interestingly, having a positive self-perception of aging could protect the underperformance caused by STT.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.4
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• pp.52-62
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• 2017

The study for the performance characteristics of the nozzleless booster used in ramjet booster was carried out. Performances related to pressure and thrust for nozzleless booster are lower than classical motor those because of absence of convergent and divergent sections of nozzle. To solve this problem, it developed a high-performance propellant with maximum impulse density included Al as metal fuel. Using the nozzleless booster casted the propellant, ground test of it was carried out by varying the length-to-diameter ratio (L/D ratio) of the propellant. Specific impulse of nozzleless booster was limited to about 75 percents of its value compared with that of classical motor adapted nozzle in the same propellant and propellant length and will be estimated approximately 85 percents of its value compared with that of classical motor at same average pressure in terms of the curve fitting by our test results.

• The KIPS Transactions:PartC
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• v.10C no.7
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• pp.899-914
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• 2003

It is generally accepted that self-similar (or fractal) processes may provide better models for teletraffic in modern telecommunication networks than Poisson Processes. If this is not taken into account, it can lead to inaccurate conclusions about performance of telecommunication networks. Thus, an important requirement for conducting simulation studies of telecommunication networks is the ability to generate long synthetic stochastic self-similar sequences. Three generators of pseudo-random self-similar sequences, based on the FFT〔20〕, RMD〔12〕 and SRA methods〔5, 10〕, are compared and analysed in this paper. Properties of these generators were experimentally studied in the sense of their statistical accuracy and times required to produce sequences of a given (long) length. While all three generators show similar levels of accuracy of the output data (in the sense of relative accuracy of the Horst parameter), the RMD- and SRA-based generators appear to be much faster than the generator based on FFT. Our results also show that a robust method for comparative studies of self-similarity in pseudo-random sequences is needed.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.53-56
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• 2019

본 논문에서는 화력을 이용하는 대형 파워 플랜트 설비의 미세먼지 발생량을 저감시키고 능동적으로 제어 할 수 있는 효율적인 시스템을 제안한다. 이 시스템은 기존의 고정형으로 설계된 집진기 방식의 고정부하량 한계점과 극복하고 초미세먼지 PM2.5, 미세먼지 PM10의 발생량에 따라 IoT센서 감지에 의해 지능형 알고리즘으로 효율적으로 저감 제어 처리량을 극대화하고, 미세먼지 발생량을 최소화한다. 또한 이 시스템의 차별성은 기존의 집진기에서 잡혀지지 않는 초미세먼지를 새로운 형태의 물질인 FAA(Fine-dust Adsorption Agent)를 통해 연료 연소 시 발생되는 초미세먼지 미세입자 자체를 크게 만들어 기존 설비 집진기 필터에 포집되게 하는 혁신적인 방식이다. 이번 연구를 통해 350도~1000도 열원에서 작용할 수 있는 화학물질 FAA 용액(Agent)을 개발 하였으며 지능형 AI 분사장치를 통해 연료에 첨가되어 연소 시 미세먼지를 20배~50배까지 볼륨을 확대시켜 기존 집진필터에 포집될 수 있게 동작된다. 이때, 기존 설계된 집진기의 한계(부하)용량에 상관없이 미세먼지 발생량을 상황인식 반응형 알고리즘(AI제어) 통해 분사량을 능동적으로 조절하여 미세먼지 발생량을 저감하는 진보적 혁신성을 지닌다.

• Clean Technology
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• v.21 no.4
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• pp.224-228
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• 2015

Phospholipase D (PLD) was immobilized on a submicro-porous membrane through covalent immobilization. The immobilization was conducted on the porous membrane surface with the treatment of polyethyleneimine, glutaraldehyde, and the anhydrase, in sequence. The immobilization was confirmed using X-ray photon spectrometer. The pH values of phosphatidylcholine (PC) dispersion solution with buffer were monitored with respect to time to calculate the catalytic activities of PC for free and immobilized PLD. The catalytic rate constant values for free PLD, immobilized PLD on polystyrene nanoparticles, and immobilized PLD on a porous cellulose acetate membrane were 0.75, 0.64, and 0.52 s^-1, respectively. Reusability was studied up to 10 cycles of PC hydrolysis. The activity for the PLD immobilized on the membrane was kept to 95% after 10 cycles, and comparable to the PLD on the nanoparticles. The stabilities for heat and storage were also investigated for the three cases. The results suggested that the PLD immobilized on the membrane had the least loss rate of the activity compared to the others. From these studies, the porous membrane was feasible as a carrier for the PLD immobilization in the production of phosphatidic acid.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.51-59
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• 1998

The purpose of this study was to evaluate the effectiveness of gargling solution with 0.05% NaF and 10% Xylitol in orthodontic patients with fixed appliance. The sample consisted of 30 adolescent patients who were classified into an experimental group and a control group, 15 patients each. Experimental group was used experimental gargling solution and the control group was used with placebo solution. The change of S. mutans in saliva was observed by $Cariescreen^R$ SM kit at pre and post 2, 4, 6, 8 weeks. The results were as follows 1. There were significant reduction in the number of S. mutans in saliva between pre and post 2 weeks(p<0.01), 4 weeks(p<0.05), 6 weeks(p<0.001), and 8 weeks(p<0.001) in experimental group. And significant reduction also were observed in the number of S. mutans in saliva between post 2 weeks, 6 weeks(p<0.05), and 8 weeks(p<0.05), but no significant reduction were showed in control group. 2. There were significant correlation in the number of S. mutans between each measurement time(pre and post 2, 4, 6, 8 weeks) in control group. 3. There were no correlation between pre and post 2 weeks, but significant correlation were observed between 2, 4, 6, 8 weeks in experimental group.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.1
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• pp.19-25
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• 2009

Purpose: We report mid to long - term results of meniscal transplantation and evaluate the important factors for successful outcomes. Materials and Methods: Between December 1999 and September 2002, 25 meniscal transplantations were performed using fresh frozen allograft. The lateral meniscus was transplanted in 19 cases and medial meniscus in 6 cases. The mean age was 34 years (range, 17~50 years) and the mean follow up was 54.8 months (range, 6~85 months). Preoperative measurements were made using a ruler graded in millimeters. Lateral meniscus was fixed by keyhole technique and medial meniscus was fixed by double bone plug technique with suturing the periphery of the meniscal transplant. All patients were evaluated with Knee Assessment Scoring System (KASS), Lysholm knee score, and Tegner activity scale for daily activity. Results: Symptoms improved in all cases. The average KASS score increased from 61.7 preoperatively to 83.8 postoperatively. The average Lysholm knee score increased from 77.7 preoperatively to 87.7 postoperatively (excellent in 3 cases, good in 17 cases, fair 4 cases, poor 1 case). But painful swellings were 3 cases, numbness in 1 case, and granuloma due to non-absorbable suture material in 1 case. Peroneal nerve palsy in 1 case was recovered after 6 weeks postoperatively. Conclusion: Meniscal allograft transplantation after subtotal or total menisectomy can significantly relieve pain and improve function of the knee joint. The exact preoperative sizing and secure fixation are essential for successful outcomes.