역삼투용막의 나선형 모듈화에 따른 성능변화

박석우,박용석,장호남 ( Seok Woo Park,Yong Seok Park,Ho Nam Chang ) 한국화학공학회 1990 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.28 No.1

Permeation characteristics of NaCl solution were studied using a cellulose acetate reverse osmosis spiral-wound module. The pure water permeability through the module was 0.272 L/㎡h atm which amounted to 13 % of the cell test. The lower permeability of the module is attributed to the permeate flow resistance through the support inserted between the two membrane envelopes. As the pressure was increased, the permeability and salt rejection increased. The permeability and the flux were dependent on the inlet flow rate to the module and the way of packing. For a uniform flow distribution in the module, several distributor tips were designed, among which 30˚cone-type distributor was found to be most suitable.

국내 시판 중인 일부 과일 리큐어의 치아 부식능 평가

박석우(Seok-Woo Park),김상겸(Sang-Kyeom Kim),정은하(Eun-Ha Jung),권호근(Ho-Keun Kwon),김백일(Baek-Il Kim) 대한치과의사협회 2016 대한치과의사협회지 Vol.54 No.7

Purpose: The aim of this study was to evaluate the erosive potential of several fruit-flavored liquors marketed in Korea by measuring pH, titratable acidity, and variations in pH utilizing an ISO method. Materials and Methods: Six fruit-flavored liquors were investigated. An orange juice and three kinds of soju were selected as the control beverage. The pH and titratable acidity of the beverages were determined by 1 M NaOH until the pH 5.5 and 7.0 (recorded as TA5.5 and TA7.0, respectively). All measurements were performed in triplicate. The process of ISO 28888 was used for measurement of the pH variation (ΔpH) using an under-saturated hydroxyapatite solution (screening solution) and determining the difference between the initial and final pH of the screening solution. The average ΔpH was determined based on 4 measurements. Results: All the fruit-flavored liquors tested in this study showed a ΔpH lower than the critical pH for dental erosion (4.5). The average pH of the fruit-flavored liquors was 2.77 and was also lower than the pH of the soju and an orange juice (control drinks). TA5.5 and TA7.0 values of the fruit-flavored liquors were 4.92㎖ and 7.13㎖, respectively. The fruit-flavored liquors showed an erosive potential capable of damaging the enamel surfaces, whereas the orange juice had the highest titratable acidity. The changes in pH determined using the screening solution confirmed that the fruit-flavored liquors had erosive potential, with ΔpH value of 1.53. Conclusions: The fruit-flavored liquors tested in this study might have a strong potential to erode dental hard tissues.

5G 네트워크 슬라이스 분류를 위한 기계학습 모델 성능 분석

박석우(Seok-Woo Park),문강현(Kang-Hyun Moon),나인호(In-Ho Ra) 한국콘텐츠학회 2023 한국콘텐츠학회 종합학술대회 논문집 Vol.2023 No.5

체중 감량을 위해 내원한 환자들에 대한 임상적 고찰

박석우 ( Seok Woo Park ),금동호 ( Dong Ho Keum ) 대한한의학회 한방재활의학과학회 2000 한방재활의학과학회지 Vol.10 No.1

5G 및 B5G 네트워크에서 그래프 신경망 및 강화학습 기반 최적의 VNE 기법

박석우(Seok-Woo Park),문강현(Kang-Hyun Moon),정경택(Kyung-Taek Chung),나인호(In-Ho Ra) 한국스마트미디어학회 2023 스마트미디어저널 Vol.12 No.11

5G 및 B5G(Beyond 5G) 네트워크의 등장으로 기존 네트워크 한계를 극복할 수 있는 네트워크 가상화 기술이 주목받고 있다. 네트워크 가상화의 목적은 효율적 네트워크 자원의 활용과 다양한 전송요구 서비스에 대한 솔루션을 제공하기 위함이다. 이와 관련하여 여러 가지 휴리스틱 기반의 VNE 기법이 연구되고 있으나 네트워크 자원 할당 및 서비스의 유연성이 제한되는 문제점을 지니고 있다. 본 논문에서는 다양한 응용의 서비스 요구사항을 충족하기 위해 GNN 기반의 네트워크 슬라이싱 분류 기법과 최적의 자원할당을 위한 RL 기반 VNE 기법을 제안한다. 제안된 기법에서는 Actor-Critic 네트워크를 이용하여 최적의 VNE를 수행한다. 또한 성능 평가를 위해 제안된 기법과 기존의 Node Rank, MCST-VNE, GCN-VNE 기법과의 성능을 비교분석하고 서비스 수용률 제고 및 효율적 자원 할당 측면에서 성능이 향상됨을 보인다 With the advent of 5G and B5G (Beyond 5G) networks, network virtualization technology that can overcome the limitations of existing networks is attracting attention. The purpose of network virtualization is to provide solutions for efficient network resource utilization and various services. Existing heuristic-based VNE (Virtual Network Embedding) techniques have been studied, but the flexibility is limited. Therefore, in this paper, we propose a GNN-based network slicing classification scheme to meet various service requirements and a RL-based VNE scheme for optimal resource allocation. The proposed method performs optimal VNE using an Actor-Critic network. Finally, to evaluate the performance of the proposed technique, we compare it with Node Rank, MCST-VNE, and GCN-VNE techniques. Through performance analysis, it was shown that the GNN and RL-based VNE techniques are better than the existing techniques in terms of acceptance rate and resource efficiency.

태양추적 기반 태양광 발전기 적용에 따른 디젤 발전량 감소 연구

박석우(Seok-Woo Park),박진완(Jin-Wan Park),백승묵(Seung-Mook Baek) 대한전기학회 2019 대한전기학회 학술대회 논문집 Vol.2019 No.7

세대별 QLF 기기의 평활면 비와동형 법랑질 우식 병소 탐지에 관한 진단정확도 비교

박석우(Seok-Woo Park),이형석(Hyung-Suk Lee),김상겸(Sang-Kyeom Kim),이은송(Eun-Song Lee),Elbert de Josselin de Jong,김백일(Baek-Il Kim) 대한치과의사협회 2018 대한치과의사협회지 Vol.56 No.1

Purpose: The aim of in vitro study was to compare the diagnostic accuracy to detect non-cavitated enamel caries on smooth surface by using four kinds of the QLF devices. Materials and Methods: A total of 52 human permanent premolars and molars were used. Fluorescence images were captured by the QLF devices (Inspektor Pro, QLF-D, Qraycam, and Qraypen). Fluorescence loss of the QLF was calculated. The severity of lesions was categorized into the following 3 scores using polarized light microscopy: normal (S), enamel demineralization to outer half of enamel (D1), and inner half of the enamel up to the dentin-enamel junction (D2). The Kruskal-Wallis test was used to compare the fluorescence loss among the QLF devices. Spearman rank correlation coefficient between histological scores and fluorescence loss of the devices was calculated. The sensitivity, specificity, and area under the receiver operating curve (AUROC) were calculated to compare their diagnostic accuracies. Results: The correlation coefficients between histological scores and the fluorescence loss of the devices showed 0.77 to 0.81 (P < 0.001). All histological scores, the fluorescence loss among the devices showed no statistical difference. Among the devices, sensitivity, specificity, and AUC values of the fluorescence loss showed 0.84 to 0.94, 0.76 to 0.90, and 0.90 to 0.92, respectively. Conclusions: All QLF devices had no difference with excellent diagnostic accuracies to detect non-cavitated enamel caries on smooth surface.

EH-WSN에서 에너지 효율 향상 및 전송지연 축소를 위한 MAC 프로토콜 설계

박석우(Seok Woo Park),나인호(In-Ho Ra) 한국스마트미디어학회 2019 스마트미디어저널 Vol.8 No.2

최근의 에너지 하베스팅 무선 센서 네트워크에 대한 연구는 제한된 에너지 자원 문제를 해결하여 네트워크 수명을 효율적으로 연장시킬 수 있는 기술 개발에 집중되고 있다. 에너지 하베스팅 기술은 무선신호에 포함된 에너지를 이용하여 배터리를 충전 시킴으로써 네트워크 수명을 지속적으로 연장시킬 수 있는 장점을 지니고 있으나 에너지를 수확하는 시간 동안에는 데이터를 전송할 수 없기 때문에 에너지 수확양이 증가할수록 데이터 전송지연도 증가하는 문제점을 지니고 있다. 이에 따라 에너지 하베스팅 무선 센서 네트워크를 설계할 때에는 네트워크 수명 연장뿐만 아니라 전송지연 축소 문제를 모두 고려하여야 한다. 본 논문에서는 네트워크에 유입되는 트래픽 양과 수확되는 에너지양에 따라 데이터 전송에 필요한 에너지를 계산하고 패킷 데이터의 전송 시간을 조절함으로써 종단간 네트워크 지연을 최소화하는 MAC 프로토콜을 제안한다. 이를 위해 에너지 수확 시간을 측정하여 네트워크의 수면 시간을 조절하는 에너지 관리 메커니즘을 설계한다. 또한, 시뮬레이션을 이용한 성능평가를 통하여 기존의 MAC 프로토콜보다 에너지 소비량과 종단간 지연 측면에서 성능이 향상됨을 보인다. Recent research on energy harvesting wireless sensor networks is focused on the development of techniques to solve the limited energy resource problem and to extend the whole network life efficiently. Energy harvesting technology can increase the lifetime of a network, but data transmission is not available when it harvests energy from radio frequency which results in longer network delay due to increased time in energy harvesting. Therefore the energy harvesting wireless sensor network should be designed considering the network delay as well as the network lifetime problem. In this paper, we propose a new MAC protocol that minimizes end-to-end network delay by adjusting the data transmission time for a packet based on the estimating the energy for data transmission along with the amount of traffic flowing into the network and harvested energy. For this goal, it proposes an energy management mechanism that adjusts the sleep time of the network by measuring energy harvesting time. In addition, with simulation results it shows that the proposed MAC protocol improves the performance in terms of energy consumption and end-to-end delay compared to the existing MAC protocols.

태권도, 축구, 체조 선수들의 균형능력과 근력, 근지구력의 상관분석

박석우 ( Seok Woo Park ),류영 ( Young Ryu ),김규완 ( Kew Wan Kim ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.1

The purpose of this study was to investigate a relationship among Taekwondo, soccer and gymnastic athletes their balance ability and lower extremity muscle strength, muscle endurance and also whether these variables show differences by sports type. For this purpose, 10 Taekwondo athletes, 10 soccer athletes and 10 gymnastic athletes that is a high school in I area were selected and their balance ability, isokinetic muscle strength and muscle endurance were measured by using force platform (AMTI) and isokinetic measurement (HUMAC NORM). Then the following results were obtained by conducting pearson product-moment correlation analysis and one-way ANOVA. In case of both right and left foot one-leg standing with open-eyes, there was a relation between both knee extension maximal muscle strength of Taekwondo, soccer, gymnastic athletes and balance ability, and in case of right foot one-leg standing with open-eyes, there was a relation between that is right plantar flexion and dorsi flexion maximum muscle strength and muscle endurance of Taekwondo, soccer, gymnastic athletes and their balance ability. Furthermore, in case of left dorsi flexion maximum muscle strength, there were significant differences in order of Taekwondo, gymnastics and soccer, and for isokinetic plantar flexion maximum muscle endurance, both right and left showed significant differences in order of Taekwondo, gymnastic and soccer.

홍화자 extract가 난소적출로 유발된 흰쥐의 골에 미치는 영향에 대한 형태계측학적 연구

박석우 ( Seok Woo Park ),박영회 ( Young Hoi Park ),금동호 ( Dong Ho Keum ) 한방재활의학과학회 2003 한방재활의학과학회지 Vol.13 No.1

Object : This study was carried out to investigate histomorphologic effect of Carthami Semen Extract On Osteoporosis In Ovariectomized Rats Methods : We used 15 female Sprague-Dawley rats. They were divided three groups, control and sham operated, Carthami Semen. We stained the specimens with Goldner,s modified Masson,s Trichrome. And then we measured bone histomorphometry using bioquant computer program of image-analysis system. The measurements included static parameter and dynamic parameter. We measured the thickness of osteoid and callus, and bone volume as static parameter, and mineral apposition rate as dynamic parameter. Results and Conclusions : 1. In the change of Ca, P there was no significant change between Carthami Semen and control group. 2. The Osteoid thickness and bone volume was increased in Carthami Semen group compared with control group. 3. The Cortical thickness and MAR was not significantly changed in Carthami Semen group compared with control group. From above result, it appears that Carthami Semen have effective on osteoporosis.