Earticle

A microfluidic pump is a key component to controllably actuate fluids in Lab on a chip devices. To overcome technical issues of a diaphragm-type pump, a valveless nozzle-diffuser type pump was developed by utilizing the different flow resistance to control a dominant flow direction by means of diaphragm actuation. In this work, based on the operating mechanism of the nozzle-diffuser type pump, we propose a new concept of a valveless pump which can generate asymmetric flow through a pump chamber. In the proposed valveless pump, asymmetric flow path structures play a role of a nozzle-diffuser installed to a pump chamber. To validate the concept of the proposed valveless pump, we conducted CFD simulations for different geometries of the flow path structures. Based on the CFD simulations, we found that the dominant flow direction can be selectively manipulated by the pump actuation and an optimal shape of the asymmetric flow path structure was proposed to maximize the net mass flow rate through the pump chamber.

생태계내 생물종 분포는 환경조건에 의해 결정되므로 종의 분포를 확인하는 것은 중요하다. 본 연구는 경상북도 상주에있는 공검지를 대상으로 2012년 4월에서 10월까지 식물상을 조사하였다. 조사결과 관속식물은 69과 176속 204종 2아종29변종 5품종으로 총 240분류군이었다. 이중 특산식물은 3분류군, 식물구계학적 특정식물종은 질경이택사, 물옥잠, 노랑어리연꽃 등 11분류군, 귀화식물은 26분류군으로 귀화율은 10.8%로 나타났다. 수생식물은 31분류군으로 한국 수생식물의17.8%에 해당된다. 따라서, 습지보존을 위하여 불필요한 인간의 간섭을 최소화하고, 생태계의 변화에 대한 지속적인 모니터링을 통하여 효율적인 관리대책을 마련하는 방안이 요구된다.

Knowing how many species live in a ecosystem is a major work because of the distributions of species are determined by the environmental condition. This study was carried out to investigate the distribution of vascular plants of Gonggeom-ji,located in Sangju-si, Gyeongsangbuk-do, from April to October on 2012. The vascular plants were summarized as 240 taxa including 69 families, 176 genus, 204 species, 2 subspecies, 29 varieties, and 5 forma. Among the investigated taxa, 3 taxa of Korean endemic plants were included. Based on the list of specially designated plants by Ministry of Environment, 11taxa including Alisma orientale, Monochoria korsakowii and Nymphoides peltata were recorded. The naturalized plants were identified as 26 taxa and the ratio of naturalized index (NI) was 10.8% of vascular plants recorded. 31 taxa of hydrophytes showed 17.8% of Korea. To conservation of wetlands, we suggest that it is required to minimize for unnecessary disturbance of human and to make a strategy for effective management by continuous monitoring for ecosystem alteration.

A spiral flow path was applied to solve the problem of the existing straight flow path in the leveling shaft, a key component of the self-levelizer that can maintain the height according to the change in payload in EV, SUV. In this study, flow analysis was performed to check the velocity, pressure drop, and flow direction of oil according to the main operating conditions of the leveling shaft with a spiral flow path. As a result of the study, a leveling shaft with a spiral flow path is likely to improve fluid properties around the orifice and inlet valve under compression conditions, and it is judged to have a development application effect.

A needle-free automatic injection syringe is a device that delivers drugs into the skin and tissues using a high-speed fluid jet without using an injection needle. This technology is attracting attention as an efficient means of vaccine delivery in the veterinary and livestock fields that reduce the risk of cross-infection and require mass vaccination. In particular, animal vaccination provides various advantages over conventional needle injection methods in terms of worker safety, inoculation speed, and maintenance cost. Among these drivers, Jet Injector Nozzle's flow path design is very important in needleless automatic injection syringes. This paper was conducted to solve the problem of pressure loss at the nozzle discharge side of the existing Jet Injector in designing the flow path of the animal vaccine-free automatic injection syringe nozzle. To this end, CAE was performed and the optimum design of the flow path required by the company was performed, and a large flow rate was possible in the optimal shape design, but this focuses on the nozzle flow path, which requires a review of design additions of cylinders and motors on the rear side.

The purpose of this study is to compare and seize the type of the path of flow for nurses and living assistant, of the path of flow for evacuation and walking practice by analysis plan for the care facilities in the out-of-home service. It supposed many problem for living in the care facilities for the aged get down activity, especially their relates with difficulty in walking. And services of nurses and living assistant get mixed properties by that problem for the aged with difficulty in walking. It classified into T type, L type, H type, □ type, ─ type all the path of flow for nurses and living assistant on the longest from nursing station to each bedroom, the path of flow for evacuation from each room to exit, the path of flow for walking practice on the corridor and lobby. The three path of flow are influenced by an inner court, especially passable court is the important primary factor in the communication between the aged, a course and time required of flow.

최근 디지털 네이티브 학습자를 위한 교수방법으로 게임활용학습에 대한 관심이 증가하고 있다. 이에 본 연구 에서는 초등학교 역사수업에 맞추어 개발된 동작인식 게임을 활용하여 수업을 실시한 후 신체운동지능, 언어지 능, 몰입, 학습성과(학업성취도, 지속의향) 간 경로분석을 실시하였다. 그 결과 신체운동지능은 몰입에 직접적인 영향을 학습성과에는 간접적인 영향을 미쳤고, 언어지능은 몰입에 직접적인 영향, 그리고 학습성과에의 간접적인 영향을 미치지 않는 것으로 분석되었다. 이 결과를 통해, 동작인식 게임활용학습은 신체운동 역량이 높은 학습자 들의 학습동기 및 성과 향상을 지원할 수 있음을 기대하게 한다

Recently, there is a growing interest in learning to use games as a teaching method for digital native learners. In this study, we conducted a path analysis between bodily-kinesthetic intelligence, linguistic intelligence, flow, learning outcomes(academic achievement, persistence intention) in motion-capture game-based learning(the used game developed for elementary school history class). As a result, bodily-kinesthetic intelligence directly influenced flow and indirectly influenced learning outcomes. Linguistic intelligence did not have direct influence on flow and indirect effects on learning outcomes. Through this result, we expected that the motion-capture game-based learning improve learning motivation and performance of learners for higher bodily-kinesthetic intelligence.

본 연구는 온라인 게임 이용자들의 게임몰입을 예측하는데 있어, 개인의 셀프리더십 및 자기효능감 특성에 따른 영 향력을 경로분석을 통하여 탐색하는데 목적이 있다. 본 연구의 목적을 위해 경기도에 위치한 240명의 대학생들이 연 구에 참여하였으며 최종 228부의 설문자료를 분석하였다. 이에 따른 연구결과는 다음과 같다. 자기효능감의 하위요인 인 자신감은 게임 이용자의 게임몰입에 영향력을 가졌으나 자기조절효능감과 과제난이도선호는 유의하지 않아 부분적 인 영향력을 미치는 것으로 도출되었다. 또한 개인의 셀프리더십 중 자기비판은 자신감에, 자기설정목표와 자기존중은 모두 자기조절효능감과 과제난이도선호에 영향을 미치는 것으로 나타났다. 즉 높은 수준의 셀프리더십을 가지고 있는 대상자가 자기효능감에 긍정적 영향을 미치며, 이는 게임몰입에 부분적인 영향력을 가지고 있는 것으로 나타났다. 이 러한 연구결과를 토대로 본 연구는 게임 이용자가 게임몰입에 어떠한 과정에 의하여 도달하는지를 제안하며, 개인의 심리적 특성에 따른 게임몰입의 긍정적 영향력에 대한 시사점을 제공할 것이다.

This study was to investigate the effect of self-efficacy on game-flow among online game users and the relation between self-leadership and self-efficacy through a path analysis. For the purpose of this article, 240 students of the university located in Gyeonggi-do participated and 228 materials was used. The results of this study were as follow. Self-confidence which is a factor of self-efficacy had an effect on game-flow between online game users. However, self-regulatory efficacy and task difficulty preference was not significant, and thus self-efficacy partially affected game-flow. Also, both of self-goal set and self-respect of self-leadership had a significant effect on self-regulatory efficacy and task difficulty preference, and self-punishment affected self-confidence as well. This results shows that the individuals with high self-leadership level have a positive effect on self-efficacy, and this is partially significant on game-flow. Therefore, the present study suggests the process about how game users reach to game-flow. And also, this would provide some implications related to positive effects of game-flow according to psychological factors of the individual.

시간 종속적 가로망에 대한 최단경로 탐색은 ITS분야의 경로 일정계획과 실시간 내비게이션 시스템에서 중요한 부분을 차지한다. 본 연구에서는 매시간간격 변동적인 링크 통행속도를 고려하는 one-to-one 시간 종속적 최단시간 경로 알고리즘을 제시한다. 이를 위해, 먼저 기존의 일반적인 최단거리 경로 알고리즘 중에서 실제 도로망에서 비교적 빠르고 효율적인 알고리즘으로 알려져 있는 3가지의 알고리즘들, 즉, two queues 구조를 가진 Graph growth 알고리즘, approximate buckets 구조를 가진 Dijkstra 알고리즘, double buckets 구조를 가진 Dijkstra 알고리즘이 선택되었다. 이 알고리즘들은 모두 네트워크 내 하나의 노드에서 모든 노드(one-to-all)로의 최단거리 경로를 빠르게 탐색하기위해 개발되었다. 선택된 알고리즘들은 시간 종속적 도로망에 대해 하나의 출발노드에서 하나의 목적노드(one-to-one)로의 최단시간 경로 탐색이 가능하도록 확장된다. 또한, 제안된 3가지의 시간 종속적 최단시간 경로탐색 알고리즘들은 미국의 Anaheim, Baltimore, Chicago, Philadelphia 4개 도시의 실제 가로망에 적용하여 검증·평가된다. 결과적으로, 도시부 가로망을 대상으로 한 시간 종속적 최단시간 경로탐색 알고리즘으로 double buckets 구조를 가진 확장된 Dijkstra 알고리즘이 추천된다.

Finding shortest paths on time dependent networks is an important task for scheduling and routing plan and real-time navigation system in ITS. In this research, one-to-one time dependent shortest path algorithms based on link flow speeds on urban networks are proposed. For this work, first we select three general shortest path algorithms such as Graph growth algorithm with two queues, Dijkstra’s algorithm with approximate buckets and Dijkstra’s algorithm with double buckets. These algorithms were developed to compute shortest distance paths from one node to all nodes in a network and have proven to be fast and efficient algorithms in real networks. These algorithms are extended to compute a time dependent shortest path from an origin node to a destination node in real urban networks. Three extended algorithms are implemented on a data set from real urban networks to test and evaluate three algorithms. A data set consists of 4 urban street networks for Anaheim, CA, Baltimore, MD, Chicago, IL, and Philadelphia, PA. Based on the computational results, among the three algorithms for TDSP, the extended Dijkstra’s algorithm with double buckets is recommended to solve one-to-one time dependent shortest path for urban street networks.

A design method of the network for automated transporters mounted on rails is addressed for automated container terminals. In the network design, the flow directions of some path segments as well as routes of transporters for each flow requirement must be determined, while the total transportation and waiting times are minimized. This study considers, for the design of the network, the waiting times of the transporters during the travel on path segments, intersections, transfer points below the quay crane (QC), and transfer points at the storage yard. An algorithm, which is the combination of a modified Dijkstra's algorithm for finding the shortest time path and a queuing theory for calculating the waiting times during the travel, is proposed. The proposed algorithm can solve the problem in a short time, which can be used in practice. Numerical experiments showed that the proposed algorithm gives solutions better than several simple rules. It was also shown that the proposed algorithm provides satisfactory solutions in a reasonable time with only average 7.22% gap in its travel time from those by a genetic algorithm which needs too long computational time. The performance of the algorithm is tested and analyzed for various parameters.

An experiment was conducted to observe the safranine flow depth in longitudinal direction of Populus tomentiglandulosa. Longitudinal flow of safranine was considered from bottom to top end of the tree. Vessel and wood fiber were considered for the measurement of safranine flow depth. It was found that sapwood conducted safranine 12.25% higher in longitudinal direction compared with heartwood. Vessel was found the main avenue for safranine flow. Vessel conducted safranine 41.94% higher than that of wood fiber. Safranine penetrated through vessel and fiber forming a curved meniscus.

Emergency operation plans are indispensable elements for effective process safety management especially when unanticipated events occur under extreme situations. In the paper, a synthesis framework is proposed for the integration success path planning and performance analysis. Within the synthesis framework, success path planning is implemented through flow-directed signal tracing, renaming and reconstruction from a complete collection of Minimal Path Sets (MPSs) that are obtained using graph traversal search on GO-FLOW model diagram. The performance of success paths is then evaluated and prioritized according to the task complexity and probability calculation of MPSs for optimum action plans identification. Finally, an Auxiliary Feed Water System of Pressurized Water Reactor (PWR-AFWS) is taken as an example system to demonstrate the flow-directed MPSs search method for success path planning and performance analysis. It is concluded that the synthesis framework is capable of providing procedural guidance for emergency response and safety management with optimal success path planning under extreme situations.

An efficient method of constructing $textsc{k}$-minimal path sets to evaluate the reliability of a flow network is presented. The network is considered to be in a functioning state if it can transmit a maximum flow which is greater than or equal to a specified amount of flow, $textsc{k}$say, and a $textsc{k}$-minimal path set is a minimal set of branches that satisfies the given flow constraint. In this paper, under the assumption that minimal path sets of the network are known, we generate composite paths by adding only a minimal set of branches at each iteration to get $textsc{k}$-minimal path sets after possibly the fewest composition, and compute maximum flow of composite paths using only minimal path sets. Thereby we greatly reduce the possible occurrence of redundant composite paths throughout the process and efficiently compute the maximum flow of composite paths generated. Numerical examples illustrate the method.

최근 우리나라에서는 극한 강우 조건에서 발생하게 되는 토석류의 발생 빈도가 증가하고 있다. 본 논문에서는 유하부의 지형 특성에 따른 토석류 퇴적의 발생 특성을 분석하는 방법을 기술하였다. 먼저 토석류 발생 전후 비교적 근시기의 고해상도 LiDAR DEM을 차분하여 지형변화를 관측하고, 유하부 외부로의 퇴적이 관측되는 지점을 토석류의 관성으로 인해 토석류 이동이 진행된 지점으로 가정한 후, 이러한 퇴적이 발생하는 유하부의 지형 특성을 유로방향경사, 유하부의 이동 전환각도, 발생부로부터 해당 지점까지의 이동거리에 대한 표고차의 비율계수(L/H)로 표현되는 토석류의 순효율 계수 특성 항목을 이용하여 분석을 수행하였다. 이러한 방법을 2011년 7월 발생한 우면산 토석류 재해를 대상으로 하여 실험을 수행하였다. 실험결과 관성에 의한 토석류의 퇴적은 유하부의 전환각도와 큰 상관관계를 갖는 것으로 나타났으며, '전환각도/(L/H)'의 비율이 8 이상인 지점에서 관성에 의한 진행이 주로 발생함을 알 수 있었다.

Recently, the frequency of debris flow disaster has increased, which is one of the natural disasters during extremely heavy rainfall condition. This paper described the analysis method about deposition characteristics of debris flow using topographic characteristics of debris flow path. First, we observed topographic changes by differencing high- resolution LiDAR DEMs acquired before and after the occurrence of debris flow event. We assumed that deposition on outside of debris flow path was generated by movements due to the inertia of debris flows. Then, we analyzed three topographic characteristics of debris flow path: slope in flow direction, transition angle of flow path, and the net efficiency(L/H) of debris flows defined by the ratio of transport length(L) and elevation difference(H). We applied this method to Umyeon Mountain debris flow event in July 2011. The results showed that deposition on outside of debris flow path due to the inertia of debris flows was significantly related to the transition angle of debris flow path. Also, we figured out that there were more frequent such depositions in locations where the ratio of 'transition angle / (L/H)' is over 8.

A numerical study was made to choose the better turbulence model for the flow in the discharge flow path from a diffuser to a wall. In this study standard $\kappa-\epsilon$ model(SKE), RNG $\kappa-\epsilon$ model(RNG), and Reynolds stress model(RSM) were applied. In case of the flow with relatively high Reynolds number at a diffuser inlet, the pressure loss coefficients by RNG have a tendency to be near to those by SKE at small ratio(below about 0.35) of $h/D_o$, but to those by RSM at large ratio(above about 0.35). At large ratio RNG begins to enlarge the effects of rapid strain and streamline curvature. RNG & RSM are recommended as the appropriate turbulence models for this case. But it is noticeable that the velocity gradient pattern in RNG is same as in SKE, and also that the total pressure distribution in RNG is same as in RSM only at swirling flow area, same as in SKE only at main flow area.

Experiments of Counter-Current Flow Limit(CCFL or Flooding) is performed to improve the drawbacks of Wallis' Correlation which neglects the effects of channel size, channel length, injection method and the boundary conditions at the inlet of liquid and gas phase. In this study, CCFL is observed by changing shape of porous plate using air and water. Results show that as the size of porous increases, CCFL with round shape of the porous plate decreases. In the present study, a CCFL correlation is developed and the CCFL map is proposed based on the present experimental results. developed by this experimental study.

이 연구는 울릉도 나리분지 추산용천수의 유동 경로를 파악하는 것이다. 칼데라 내부 가장자리를 따라 발달하는 단층과 단열구조들의 발달 방향이 추산용천수 유동 경로에 영향을 주는 요소로 파악되었다. 추산용천수는 함양된 지하수가 동서 방향과 남북 방향의 단열대를 따라 추산용출소 방향으로 흐른다. 이와 더불어 북북동 방향으로 경사진 칼데라의 부등함몰의 영향으로 북동 내지 북북동 방향으로 흐르는 것으로 파악되었다. 장내세균과인 Entrobacteriaceae을 이용하여 나리지하수 쪽의 물이 추산용출소 방향으로 유동하는 것으로 파악되었다. 다만, 분석에 사용된 시료수가 매우 적어 성인계곡수로부터 나리분지와 추산용출소까지의 유동경로를 전체적으로 파악할 수 없다는 제한성이 있다.

This study clarified the flow path of Choosan Spring, Nari Basin, Ulleung Island, South Korea. The orientations of faults and fractures developed on the inner edge of the caldera were identified as major factors affecting the flow path. The main flow paths include fracture zones oriented N-S and E-W. The spring also flows in a NE or NNE direction under the influence of the irregular shape of the caldera, which slopes to the NNE. Using Entrobacteriaceae species as tracers, it was found that Nari groundwater flows toward Choosan Yongchulso. However, the small number of water samples used in the analysis limits our understanding of the flow path from Sungin Valley to Nari Basin and Choosan Yongchulso.

By matching a well established fast throughflow code, with standard loss correlations, and an efficient optimization algorithm, a new design system has been developed, which optimizes inlet and exit flow-field parameters for each blade row of a multistage axial flow turbine. The compressible steady state inviscid throughflow code based on streamline curvature method is suitable for fast and accurate flow calculation and performance prediction of a multistage axial flow turbine. A general purpose hybrid constrained optimization package, iSIGHT has been used, which includes the following modules: genetic algorithm, simulated annealing, modified method of feasible directions. The design system has been demonstrated using an example of a 5-stage low pressure steam turbine for 800MW thermal power plant previously designed by HANJUNG. The comparison of computed performance of initial and optimized design shows significant improvement in the turbine efficiency.

Solid oxide fuel cells (SOFCs) is the high efficiency fuel cell operating at high temperatures ranging from 700-1000℃. Design of the flow paths of the fuel and air in SOFCs is important to improve cell performance and prevent cell degradation. However, the uneven distribution of current density in the traditional type having one inlet and outlet causes cell degradation. In this regard, the parallel flow path with two inlet and outlets was designed and compared to the traditional type based on computational fluid dynamics (CFD) simulation. To check the cell performance, hydrogen distribution, velocity distribution and current density distribution were monitored. The results validated that the parallel designs with two inlets and outlets have a higher cell performance compared to the traditional design with one inlet and outlet due to a larger reaction area. In case of uniform-type paths, more uniform current density distribution was observed with less cross-sectional variation in flow paths. In case of contracted and expanded inflow paths, significant improvement of performance and uniform current density was not observed compared to uniform parallel path. Considering SOFC cell with uniform current density can prevent cell degradation, more suitable design of SOFC cell with less cross-sectional variation in the flow path should be developed. This work can be helpful to understand the role of flow distribution in the SOFC performance.

This paper presents that model 1 is to show an approach to determining unidirection or bidirection of the optimal flow path design, model 2 is to show the design of an AGV can determine the minimum number of required vehicles. Our purposes of this article are that first, it is easy to see that computationlly advanced efficient procedure with some pairwises of comparision, zero-one integer and northwest rule by using, second, to determine the minimum number of vehicles in the layout for manufacturing facility, we used a coefficient ratio with moved numbers of loaded & unloaded vehicles between stations and available time of AGV's capacity for per shift per vehicle. Example is presented to demonstrate the approach.

Numerical analysis is carried out to identify the wall thinning effect inside the feed water valve. The finite volume method is applied to make analysis for the viscous flows. The commercial cock FLUENT is used for the simulation and the GAMBIT for the grid generation. The RNG $\kappa-\varepsilon$ model is used for the turbulence and the tet-hybrid grid is applied for the modeling. The velocity vector, the pressure contour, the change of residual along the iteration number, and the dynamic head are predicted for the hydrodynamic investigation.