• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.11a
• /
• pp.651-653
• /
• 2011

본 논문에서는 모바일 노드들의 움직임이 심한 MANET 환경에서의 데이터의 전송을 안정적이고 신뢰성있게 하기 위한 방법을 제시하고자 한다. 우회경로가 적은 경우보다 우회경로가 많이 확보되었을 때 상호간의 통신이 더욱 안정적이나, 기존 연구에서는 이러한 고려가 충분히 되어있지 않고, 경로 설정 당시 알고리즘에 의해 최적화된 경로라고 판단된 경로만 기억해 놓기때문에 경로 손실이 되었을 때에 우회경로가 존재 함에도 불구하고 패킷 전송을 실패하게 된다. 본 논문에서는 확률에 기반한 안정도를 측정하고 MANET 환경에서 패킷전달 가능성이 높은 다중경로 라우팅 프로토콜 아이디어를 제시한다.

• International conference on construction engineering and project management
• /
• 2015.10a
• /
• pp.158-160
• /
• 2015

Efficient scheduling and resource management are the key factor to reduce construction project budget (e.g., labor cost, equipment cost, material cost, etc.). Resource-based line of balance (LOB) technique has been used to complement the limitations of existing time-driven scheduling techniques (e.g., critical-path method). Optimizing construction alternatives contributes to cost savings while honoring the project deadline. However, existing LOB scheduling is lack of identifying optimal resource combination. This study presents a method which identifies the optimal construction alternatives, hence achieving resource minimization in a repetitive construction by using genetic algorithm (GA). The method provides efficient planning tool that enhances the usability of the system.

• ETRI Journal
• /
• v.45 no.4
• /
• pp.557-569
• /
• 2023

Traditional deterministic channel modeling is accurate in prediction, but due to its complexity, improving computational efficiency remains a challenge. In an alternative approach, we investigated a multilayer artificial neural network (ANN) to predict large-scale and small-scale channel characteristics in metro tunnels. Simulated high-precision training datasets were obtained by combining measurement campaign with a ray tracing (RT) method in a metro tunnel. Performance on the training data was used to determine the number of hidden layers and neurons of the multilayer ANN. The proposed multilayer ANN performed efficiently (10 s for training; 0.19 ms for prediction), and accurately, with better approximation of the RT data than the single-layer ANN. The root mean square errors (RMSE) of path loss (2.82 dB), root mean square delay spread (0.61 ns), azimuth angle spread (3.06°), and elevation angle spread (1.22°) were impressive. These results demonstrate the superior computing efficiency and model complexity of ANNs.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.3
• /
• pp.1-14
• /
• 2008

Mass transit information should contribute many benefits to users. Especially transportation information technology is developing highly with information technology in Korea recently. Hereafter it is expected to provide customized transportation information to users individually with the advent of ubiquitous age in earnest. This public transportation information service can be realized by path finding algorithms in public transportation networks including travel and transfer attributes. In this research, multi objectives such as travel time, transfer time, and number of transfer and so on are constructed with the primary facts influencing users. Moreover, the method reducing user's path finding alternatives arbitrarily is proposed by selecting the best alternative which provides maximum utility to users among non dominated paths. Therefore, the ultimate goal of this study proposes a multi objective shortest paths finding algorithm which can take into account multiple user classes in a transit network with multiple travel modes. The proposed algorithm is demonstrated based on the two case studies - a small toy network and the large-scaled Seoul Metropolitan subway network.

• Tunnel and Underground Space
• /
• v.28 no.6
• /
• pp.596-608
• /
• 2018

As urban infrastructure is aging, the possibility of accidents due to the failures or breakdowns of infrastructure increases. Especially, aging underground infrastructures like sewer pipes, waterworks, and subway have a potential to cause an urban ground sink. Urban ground sink is defined just as a local and erratic collapse occurred by underground cavity due to soil erosion or soil loss, which is separated from a sinkhole in soluble bedrock such as limestone. The conventional measurements such as differential settlement gauge, inclinometer or earth pressure gauge have a shortcoming just to provide point measurements with short coverage. Therefore, these methods are not adequate for monitoring of an erratic subsidence caused by underground cavity due to soil erosion or soil loss which occurring at unspecified time and location. Therefore, an alternative technology is required to detect a change of underground physical condition in real time. In this study, the feasibility of a novel magnetic resonance based monitoring method is investigated through laboratory tests, where the changes of path loss (S21) were measured under various testing conditions: media including air, water, and soil, resonant frequency, impedance, and distances between transmitter (TX) and receiver (RX). Theoretically, the transfer characteristic of magnetic field is known to be independent of the density of the medium. However, the results of the test showed the meaningful differences in the path loss (S21) under the different conditions of medium. And it is found that the reflection coefficient showed the more distinct differences over the testing conditions than the path loss. In particular, input reflection coefficient (S11) is more distinguishable than output reflection coefficient (S22).

• Journal of Science Education
• /
• v.35 no.2
• /
• pp.173-192
• /
• 2011

The purpose of this study was to develop inquiry modules for learning straight propagation of light, to verify their efficiency, and to acquire implications. this study proposes teaching modules for improvements of light experiments, which were developed in this work. Inquiry modules were applied to 75 school teachers(8 elementary school teachers, 67 middle school and high school teachers) for examining that the modules make teachers have the scientific concepts. Then, conception changes were analyzed except 5 teachers who responded poorly. The pre-test result shows that most teachers have alternative conceptions, which is that they thought the bright shape on apparatus's bottom panel itself shown in the textbook as evidence for the path of light's straight propagation. The post-test result shows this alternative conception was changed into scientific conception. Unlikely pretest, most teachers' conception was changed into the scientific conception that the light come from a light source. Teachers are able to express that the light beam comes from a miniature electric bulb. Further more, most teachers can draw light's path correctly; from the miniature electric bulb, through vertical panel having a hole, to the apparatus bottom.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.9
• /
• pp.25-32
• /
• 2009

Recently, research for Network-on-chip(NoC) is progressing. However, due to the increase of system complexity and demand on high performance, conventional copper-based electrical interconnect would be faced with the design limitation of performance, power, and bandwidth. As an alternative to these problems, combined use of Electrical Interconnects(EIs) and Optical Interconnects(OIs) has been introduced. In this paper we propose efficient routing optimization strategy and hybrid switch architecture, which use OIs for critical path and EIs for non-critical path. The proposed method shows up to 25% performance improvement and 38% power reduction.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.3
• /
• pp.1011-1018
• /
• 2015

This study was conducted to investigate the plasma phosphoproteome and differential plasma phosphoproteins in cases of of Opisthorchis viverrini (OV)-related cholangiocarcinoma (CCA). Plasma phosphoproteomes from CCA patients (10) and non-CCA subjects (5 each for healthy subjects and OV infection) were investigated using gel-based and solution-based LC-MS/MS. Phosphoproteins in plasma samples were enriched and analyzed by LC-MS/MS. STRAP, PANTHER, iPath, and MeV programs were applied for the identification of their functions, signaling and metabolic pathways; and for the discrimination of potential biomarkers in CCA patients and non-CCA subjects, respectively. A total of 90 and 60 plasma phosphoproteins were identified by gel-based and solution-based LC-MS/MS, respectively. Most of the phosphoproteins were cytosol proteins which play roles in several cellular processes, signaling pathways, and metabolic pathways (STRAP, PANTHER, and iPath analysis). The absence of serine/arginine repetitive matrix protein 3 (A6NNA2), tubulin tyrosine ligase-like family, member 6, and biorientation of chromosomes in cell division protein 1-like (Q8NFC6) in plasma phosphoprotein were identified as potential biomarkers for the differentiation of healthy subjects from patients with CCA and OV infection. To differentiate CCA from OV infection, the absence of both serine/threonine-protein phosphatase 2A 56 kDa regulatory subunit beta isoform and coiled-coil domain-containing protein 126 precursor (Q96EE4) were then applied. A combination of 5 phosphoproteins may new alternative choices for CCA diagnosis.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.10
• /
• pp.415-420
• /
• 2020

Crowd flows occur in metropolitan railway transit stations, terminals, multiple buildings, and stadiums and are important in ensuring the safety as well as smooth flow of pedestrians in these facilities. In this study, the author developed a new computational analysis method for crowd flow dynamics and applied it to models of transit connecting paths. Using the analysis method, the potential value of the exit was assigned the smallest value, and the potential value of the surrounding grids gradually increased to form the overall potential map. A pathline map was then constructed by determining the direction vector from the grid with large potential value to the grid and small potential. These pathlines indicate basic routes of passenger flow. In all models of the analysis object, the pedestrians did not move to the first predicted shortest path but instead moved using alternative paths that changed depending on the situation. Even in bottlenecks in which pedestrians in both directions encountered each other, walking became much smoother if the entry time difference was dispersed. The results of the analysis show that a method for reducing congestion could be developed through software analysis such as passenger flow analysis without requiring hardware improvement work at the railway station.

• Journal of Korea Spatial Information System Society
• /
• v.10 no.1
• /
• pp.51-63
• /
• 2008

Previous studies for routing In USN (Ubiquitous Sensor Networks) appear to be unreliable due to the dependence on non-spatial data and the lack of map overlay analysis. Multiple spatial parameters and radio propagation modeling techniques were integrated to derive RSSI (Received Signal Strength Indicator) value between route nodes and produce a highly reliable path map. It was possible to identify area-wide patterns of USN route subject to many different Influences (e.g. the specific effects of radio blocking factors such as the visible area, road area, cell duplicated area, and building density), which cannot be acquired by traditional non-spatial modeling. The quantitative evidence concerning the USN route for individual cell as well as entire study area would be utilized as major tools to visualize paths in real-time and to select alternative path when failure or audition of route node occurs.