• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.101-108
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• 2007

There nay be collisions among beacons from several full function devices in IEEE 802.15.4 sensor networks. These collision of beacons may cause devices to lose time synchronization, and thus be unable to association. To solve this problem, the IEEE 802.15.4b defines a new Post Beacon Period(PBP), but it does not still alleviate the beacon collision problem. In this paper, we propose two automatic beacon alignment schemes that a node itself can decide its beacon start time using its short address that has been assigned during association. We also simulate and investigate our proposed automatic beacon collision avoidance schemes using NS-2 simulator.

• PNF and Movement
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• v.16 no.3
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• pp.345-353
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• 2018

Purpose: The purpose of the present study was to compare the effects of proprioceptive neuromuscular facilitation (PNF) and static stretching on weight distribution and flexibility for trunk flexion. Method: Sixty participants who had no musculoskeletal disorders were recruited from a local university within six months of this study. The participants were randomly assigned to a PNF stretching group (N=30) and a static stretching group (N=32). For the pre-and post-measurement design, the left-right weight distribution, anterior-posterior weight distribution, and finger-to-floor distance (FFD) were measured before and after the stretching interventions. Result: The FFD results were significantly improved after the interventions, regardless of the group differentiation (p<0.05). The PNF stretching intervention significantly increased the differences between anterior and posterior weight distribution compared to the static stretching group (p<0.05). Conclusions: Both the PNF and static stretching interventions could improve flexibility for trunk flexion mobility. Although the PNF intervention improved the weight distribution in the anterior-posterior direction, further research is required to investigate the various PNF interventions on left-and-right and anterior-posterior weight distribution.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2237-2243
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• 2020

Background: The myofascial release technique is known to be an effective technique for increasing posterior fascia flexibility in short hamstring syndrome (SHS) subjects. But therapeutic mechanism of myofascial relaxation remains unclear. Recently, the theory of autonomic nervous system domination has been raised, however, a proper study to test the theory has not been conducted. Objectives: To investigate whether the application of the myofascial release technique can induce changes in the autonomic nervous system and affect the secretion of stress hormones and myofascial relaxation. Design: Quasi-experimental study. Methods: Twenty-four subjects with SHS were randomly divided into two groups. In the experimental group, the suboccipital muscle inhibition (SMI) technique was applied to the subjects for 4 min in supine position, and in the control group, the subjects were lying in the supine position only. A forward flexion distance (FFD) was conducted, blood pressure, heart rate, and cortisol levels were measured before and after the intervention and 30 min after intervention to determine myofascial relaxation and stress hormone levels. The evaluation was conducted separately in blind by an evaluator. Results: A FFD decreased in the experimental group, no change in cortisol was observed. On the contrary, a decrease in cortisol appeared in the control group after 30 minutes. Conclusion: The myofascial release technique is an effective treatment to increase the range of motion through posterior superior myofascial chain, but there is no evidence that myofascial release technique can control the autonomic nervous system.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.52-61
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• 2017

Considering its significant impact on the cost and schedule of construction projects, formwork as one part of temporary facility categories in construction should be arranged precisely. Current practice in the formwork planning is often conducted manually and repetitively, causing low efficiency and time waste. This study proposes an automated framework to generate more accurate and detailed formwork plans by utilizing information from building information modeling (BIM) considering the adequate geometric and semantic information provided by the BIM model. The dimensions and quantities information of elements in a building can be extracted automatically. Then, a rule is prepared for calculating the required forms erected around elements based on the contact areas. Finally, an algorithm of integrating first fit decreasing (FFD) with coordinated bottom left (CBL) is applied to automatically generate the formwork plan. The BIM-based automated planning framework is demonstrated by an illustrative example. The results show that the proposed framework can generate the formwork plan accurately and automatically, and significantly improve the efficiency in the formwork plan and reuse.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.237-244
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• 2011

In this paper, a feature-based registration technique is proposed for pre-contrast and post-contrast lung CT images. It utilizes three dimensional(3-D) features with their descriptors and estimates feature correspondences by nearest neighborhood matching in the feature space. We design a transformation model between the input image pairs using a free form deformation(FFD) which is based on B-splines. Registration is achieved by minimizing an energy function incorporating the smoothness of FFD and the correspondence information through a non-linear gradient conjugate method. To deal with outliers in feature matching, our energy model integrates a robust estimator which discards outliers effectively by iteratively reducing a radius of confidence in the minimization process. Performance evaluation was carried out in terms of accuracy and efficiency using seven pairs of lung CT images of clinical practice. For a quantitative assessment, a radiologist specialized in thorax manually placed landmarks on each CT image pair. In comparative evaluation to a conventional feature-based registration method, our algorithm showed improved performances in both accuracy and efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.230-230
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• 2009

가스절연 개폐장치 (Gas Insulated Switchgear : GIS)의 고체 스페이서에 경사 기능성 재료 (Functionally Graded Material : FGM)가 적용될 때, 절연성능이 크게 향상된다. 본 논문에서는 FGM 스페이서가 적용된 GIS의 전극 및 스페이서의 형상을 변경하여 최대전계를 완화시켰다. 이를 위해 완전요인실험 (Full Factorial Design : FFD)과 결합된 반응표면법 (Response Surface Methodology : RSM)의 최적화기법을 이용하여, 전극 및 스페이서의 최적 형상을 설계하였다.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.219-224
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• 2006

3 차원 입력 장치는 키보드나 마우스 같은 일반적인 입력 장치로는 받아 들이기 어려운 3 차원 입력을 사용자로부터 간편하고 직관적인 방법으로 받아들일 수 있다는 측면에서 활발히 연구 및 사용되고 있다. 또한 햅틱 장치는 가상 물체의 조작에 따른 시각적인 피드백 외에 가상 물체의 느낌을 피드백 힘을 통해 사용자에게 전달해 줌으로써 컴퓨터와 사용자간의 상호 작용에 큰 도움을 준다. 본 논문은 햅틱 피드백이 적용된 실시간 가변형 모델과 효과적인 3 차원 입력에 대한 기반 연구를 하고자 한다. 그리고 이에 대한 한 가지 사례로써 햅틱 장치를 이용한 가상 판화 시스템을 제작 한다. 가상 판화 시스템은 시각 처리 부분과 촉각 처리 부분, 그리고 사용자의 3 차원 입력을 돕는 인터페이스 부분으로 구성되어 있다. 시각 처리 부분은 3 차원 공간 상에서 사용자의 조각에 따른 판화 표면의 변형을 처리하며 촉각 처리 부분은 실제 판화를 제작할 때 느끼는 촉각을 햅틱 인터페이스를 이용하여 사용자에게 전달한다. 이를 위해 먼저 시각 처리 부분에서는 NURBS 기반의 자유 형상 변형 (FFD)기법을 이용하였는데 가상 조각도에 의한 물체 표면의 지역적인 변형을 구현하기 위해 조각도가 닿는 부분에 대해 기조 격자점 (control point)을 증가시켜 원하는 부분에 대한 지역적인 변화를 용이하도록 하였고 다음으로 촉각 처리 부분에서는 S-chain 모델을 이용하였는데 S-chain 모델을 객체 전체에 적용하지 않고 접촉이 일어날 경우 그 접촉점을 기준으로 S-chain 모델을 지역적으로 적용하는 방법을 고안하여 실제 구현에 이용하였다. 인터페이스 적인 측면에서 사용자의 3 차원 입력장치를 통한 인터렉션은 사용자로 하여금 보다 자유로운 입력을 허용하지만 이에 따른 깊이 지각 문제를 발생시킨다. 이러한 문제를 최소화 시키고 사용자의 깊이 지각을 강화시키기 위해 사용자에게 제공되는 시각적 자극을 변형시키고 다양한 정보를 제공하도록 하였다. 가상 판화 시스템은 가상 환경에서 사용자의 조작에 따른 다양한 결과물을 제작 및 출력해 볼 수 있도록 해준다. 또한 가상 환경에서 이러한 기반을 제공함으로써 가상 환경의 장점인 복사, 이동 및 영구 보존 특성을 동시에 얻을 수 있다. 본 논문은 이러한 작업을 위한 기반 기술로써 햅틱 및 가변형 모델, 3 차원 입력 장치에 대한 시각적 인터페이스에 대해 다루고 이 기반 기술을 바탕으로한 가상 판화 시스템의 구현에 대하여 논하고자 한다.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.66-72
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• 2010

Pediococcus pentosaceus SA131 was isolated from jeotgal, is the bacteriocin producer against bovine mastitis pathogens, Streptococcus uberis E290, Enterococcus gallinarum E362, and Staphylococcus epidermidis ATCC 12228. The medium composition for pediocin SA131 production by P. pentosaceus SA131 was optimized using response surface methodology. Component of medium was studied as carbon source (glucose, fructose, lactose, glycerol, sucrose, maltose, and mannitol), nitrogen source (beef extract, yeast extract, peptone, malt extract, and tryptone), mineral and surfactant ($MgSO_4$, $KH_2PO_4$, $(NH_4)_2SO_4$, $MnSO_4$, NaCl, sodium acetate, and Tween 80). Through one factor-at-a-time experiment, glucose, fructose, yeast extract, malt extract, NaCl, $MgSO_4$, and Tween 80 were determined as the good ingredient. The effects of major factors for pediocin SA131 production were investigated by two-level fractional factorial designs (FFD). By a $2^4$ FFD, fructose, yeast extract, and $MnSO_4$ were found to be the important factors for the bacteriocin production. Subsequently, a $2^3$ central composite design (CCD) was adopted to derive a statistical model for optimizing the composition of the fermentation medium. The estimated optimum composition for the production of pediocin SA131 by P. pentosaceus SA131 was as follows; 0.13% fructose, 1% glucose, 1.8% yeast extract, 2.58% $MnSO_4$, 0.2% NaCl, and 0.2% Tween 80. The pediocin production under optimized medium was increased to 1,000 AU/mL, compared to the 400 AU/mL in MRS medium.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.205-213
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• 2011

The Long Term Evolution (LTE) system is designed to provide a high quality data service for fast moving mobile users. It is based on the Orthogonal Frequency Division Multiplexing (OFDM) and relies its channel estimation on the training samples which are systematically built within the transmitting data. Either a preamble or a lattice type is used for the distribution of training samples and the latter suits better for the multipath fading channel environment whose channel frequency response (CFR) fluctuates rapidly with time. In the lattice-type structure, the estimation of the CFR makes use of the least squares estimate (LSE) for each pilot samples, followed by an interpolation both in time-and in frequency-domain to fill up the channel estimates for subcarriers corresponding to data samples. All interpolation schemes should rely on the pilot estimates only, and thus, their performances are bounded by the quality of pilot estimates. However, the additive noise give rise to high fluctuation on the pilot estimates, especially in a communication environment with low signal-to-noise ratio. These high fluctuations could be monitored in the alternating high values of the first forward differences (FFD) between pilot estimates. In this paper, we analyzed statistically those FFD values and propose a postprocessing algorithm to suppress high fluctuations in the noisy pilot estimates. The proposed method is based on a localized adaptive moving-average filtering. The performance of the proposed technique is verified on a multipath environment suggested on a 3GPP LTE specification. It is shown that the mean-squared error (MSE) between the actual CFR and pilot estimates could be reduced up to 68% from the noisy pilot estimates.

• PNF and Movement
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• v.13 no.1
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• pp.31-37
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• 2015

Purpose: The purpose of this study is to compare changes in the flexibility of hamstring muscles which are relaxed on suboccipital muscle through suboccipital muscle inhibition and combination technique. Methods: Thirty sample subjects (16 male and 14 female) were randomly divided into an experimental group (n=15) and a control group (n=15). 1. Suboccipital muscle inhibition: Suboccipital muscles of the patients were placed on a bed. The occipital region was placed on a therapist's fingers, and the posture was maintained for three minutes before remeasurement. 2. Treatment with combination technique (body bolster and wooden pillow): Wooden pillows were placed where the participants could relax the posterior arch of the atlas; additional body bolsters were also placed to avoid high pressure, and the treatment was maintained for three minutes before remeasurement. Results: There was a statistical difference in finger floor distance (FFD) and straight leg raise (SLR) results for those treated with SMI (P<0.05). There was no statistical difference in FFD and SLR results for those treated with the combination technique (P>0.05). Conclusion: Between the two intervention methods; the suboccipital muscle inhibition technique was more effective in increasing the flexibility of subjects with a shortened hamstring than was the combination technique.