• Advances in robotics research
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• 제1권2호
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• pp.127-140
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• 2014

This work presents an IR-based system for parking assistance and obstacle detection in the automotive field that employs the Microsoft Kinect camera for fast 3D point cloud reconstruction. In contrast to previous research that attempts to explicitly identify obstacles, the proposed system aims to detect "reachable regions" of the environment, i.e., those regions where the vehicle can drive to from its current position. A user-friendly 2D traversability grid of cells is generated and used as a visual aid for parking assistance. Given a raw 3D point cloud, first each point is mapped into individual cells, then, the elevation information is used within a graph-based algorithm to label a given cell as traversable or non-traversable. Following this rationale, positive and negative obstacles, as well as unknown regions can be implicitly detected. Additionally, no flat-world assumption is required. Experimental results, obtained from the system in typical parking scenarios, are presented showing its effectiveness for scene interpretation and detection of several types of obstacle.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.289-292
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• 2008

Highly over-expanded nozzle of the rocket engines will be excited by non-axial forces due to flow separation at sea level operations. Since rocket engines are designed to produce axial thrust to power the vehicle, non-axial static and/or dynamic forces are not desirable. Several engine failures were attributed to the side loads. Present work investigate the unsteady flow in an over-expanded rocket nozzle in order to estimate side load during a shutdown/starting. Numerical computations has been carried out with density based solver on multi-block structured grid. Present solver is explicit in time and unsteady time step is calculated using dual time step approach. AUSMDV is considered as a numerical scheme for the flux calculations. One equation Spalart-Allmaras turbulence model is selected. Results presented here is for two nozzle pressure ratio i.e. 100 and 20. At 100 NPR, restricted shock separation (RSS) pattern is observed while, 20 NPR shows free shock separation (FSS) pattern. Side load is observed during the transition of separation pattern at different NPR.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1641-1642
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• 2015

Recently, the interest about Vehicle-to-Grid(V2G) system which can use the electric vehicles as generation sources or storage devices has rapidly increased. However, this technology does not use widely yet, and there is no clear standard or regulation for it. If electric vehicles are connected to the power system indiscreetly, it can cause problem to personnel safety and adverse effect on the power system. Therefore, it is important to analyze the related standards. In this paper, we introduce some international standard related with V2G system.

• 한국항공운항학회지
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• 제16권4호
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• pp.75-82
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• 2008

As the number of passengers and the amount of cargo is getting increased, the traffic of aircraft and moving vehicle at an airport is getting busy. Especially, due to the heavy traffic of moving vehicles in the area of airside, the safety management of them is getting important. The study has been performed for suggesting improved methods in order to reduce safety accidents between aircraft and moving vehicles by introducing a safety management system for moving vehicles in airside of an airport. In order to improve the level of safety with the efficient management of moving vehicles in airside, the analysis of the domestic and international trends of the related technology and regulations has been performed. As a result, the conceptual design of safety management system has been suggested by utilizing the location information technology and four layers (hardware, network, middleware and application) approaches of safety management system.

• 대한산업공학회지
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• 제27권1호
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• pp.18-24
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• 2001

This paper presents a model and a heuristic algorithm for the Traveling Salesman Problem with Time Windows(TSPTW). The main difference of our model compared with the previous ones lies in that the time windows we are concerned are more flexible and realistic than the previous ones. In the typical TSPTW, the service at a node must begin within the time grid called the time window that is defined by the earliest and the latest time to start the service at each node. But, in real business practice, a lateness cost is usually penalized rather than the service is prohibited at all when a vehicle arrives after the latest time. Considering this situation, we develop a model with a new time window that allows an arrival after the latest time and penalizes the late arrival by charging a lateness cost. A two-phased heuristic algorithm is proposed for the model and is extensively tested to verify the accuracy and efficiency of the algorithm.

• 조명전기설비학회논문지
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• 제27권4호
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• pp.41-47
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• 2013

The electrical relay in an essential part of the Smart Grid, Electrical Vehicle (EV) and LED lightning system. For these reasons, research of electrical relay is actively underway. In this paper, analyze of the relationship between the bouncing of relay contact and magnetic flux of permanent magnet. Experiment result, changes the bouncing numbers depending on the magnetic flux of the latching relay. And find the value of the magnetic flux that occurs to minimize the bouncing of the contacts. In additions, by the increasing the magnetic flux, unconditional bounce is not reduced. The bouncing number of latching relay is less than expected the armature relay for present results. Further experiments are need to prove it, bouncing on the armature relays.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1639-1640
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• 2015

These days most of countries concern about eco-friendly energy. With this trend, the interests for Electric Vehicles(EVs) have been increased not only for its eco-friendly characteristics but also for the possibility that it can be used as Distributed Generation(DG). However, in terms of using EVs as DG, it requires specific standards. If there is no regulation and many of EVs start to discharge, it could cause severe unstability in power system. As there is no proper standards or regulations of Vehicle-to-Grid(V2G) system, we suggest the development direction of standardization of V2G system in the Republic of Korea by examining other countries' V2G standards.

• Journal of Advanced Marine Engineering and Technology
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• 제24권5호
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• pp.33-41
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• 2000

Three dimensional flow fields around passenger car body was computed by PAM-FLOW, well-known and validated computer program for thermal and fluid analysis. Regarding the computational method, a Navier-Stokes solver based on finite element method with various turbulent models and adaptive grid technique (H-refinement)was adopted. The results were physically reasonable and compared with experimental data, giving good agreement. It was found that three dimensional flow simulation with H-refinement technique had potential for prediction of low fie이 around vehicle and the ability to predict vortex in the wake, which is vital for CFD to be used for automobile aerodynamic calculation.

• 산업경영시스템학회지
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• 제22권53호
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• pp.13-22
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• 1999

This paper presents a model and dynamic programming based algorithm for the Traveling Salesperson Problem with Time Windows (TSPTW). The main difference of our model compared with the previous ones lies in that the time windows we are concerned are far more flexible and realistic. In the typical TSPTW, the service at a node must begin within the time grid called the time window that is defined by the earliest and the latest time to start the service at the node. But, in real business practices, a lateness cost is usually penalized rather than the service is prohibited at all when a vehicle arrives after the latest time. Considering this situation, we propose a model with a new time window that allows an arrival after the latest time and penalizes the late arrival by charging a lateness cost. An algorithm introduced for the model is extensively tested to verify the accuracy and efficiency.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.803-811
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• 2014

The moment when Electrical Vehicle (EV) starts charging or discharging is one of the most important parameters in estimating the impact of EV load on the grid. In this paper, a decision-making problem of determining the start time of charging and discharging during allowed period is proposed and studied under the uncertainty of real-time price. Prospect theory is utilized in the decision-making problem of this paper for it describes a kind of decision making behaviors under uncertainty. The case study uses the parameters of Springo SGM7001EV and adopts the historical realtime locational marginal pricing (LMP) data of PJM market for scenario reduction. Prospect values are calculated for every possible start time in the allowed charging or discharging period. By comparing the calculated prospect values, the optimal decisions are obtained accordingly and the results are compared with those based on Expected Utility Theory. Results show that with different initial State-of-Charge ($SoC_0$) and different reference points, the optimal start time of charging can be the one between 12 a.m. to 3 a.m. and optimal discharging starts at 2 p.m. or 3p.m. Moreover, the decision results of Prospect Theory may differ from that of the Expected Utility Theory with the reference points changing.