• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.11
• /
• pp.1741-1746
• /
• 2022

As the use of school buses becomes more common, related laws are being enacted, such as making it mandatory for children to check school bus dropouts due to frequent accidents caused by the negligence of school bus drivers and their guardians. In this paper, we propose a safe school bus system that links efficient radio-frequency identification (RFID) and mobile APP in terms of energy utilization and cost. The school bus system uses RFID cards to check information on children boarding the school bus, and real-time SMS transmission allows parents to safely send their children to and from school. Instructors on the school bus can check their children's disembarkation information once more through APP, preventing various accidents that may occur to children left on the bus. Due to the automation of the school bus operation log, daycare center teachers can not only check the information on getting on and off, but also manage the information on the attendance and discharge of the students.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.9
• /
• pp.1081-1087
• /
• 1999

Load Flow calulation methods can usually be divided into Gauss-Seidel method, Newton-Raphson method and decoupled method. Load flow calculation is a basic on-line or off-line process for power system planning. operation, control and state analysis. These days Newton-Raphson method is mainly used since it shows remarkable convergence characteristics. It, however, needs considerable calculation time in construction and calculation of inverse Jacobian matrix. In addition to that, Newton-Raphson method tends to fail to converge when system loading is heavy and system has a large R/X ratio. In this paper, matrix equation is used to make algebraic expression and then to slove load flow equation and to modify above defects. And it preserve P-Q bus part of Jacobian matrix to shorten computing time. Application of mentioned algorithm to 14 bus, 39 bus, 118 bus systems led to identical results and the same numbers of iteration obtained by Newton-Raphson method. The effect of computing time reduction showed about 28% , 30% , at each case of 39 bus, 118 bus system.

• The Journal of the Korea Contents Association
• /
• v.11 no.8
• /
• pp.459-467
• /
• 2011

BIS(Bus Information Systems) supplies the bus arrived time information for users in using BIT(Bus Information Terminal) installed on the bus stop. BIT is the device using peoples directly. So, BIT need a quick response when it flew. These are an important factor in the strategy of the BIS maintenance. BIT need a maintenance cost to operate smoothly. So, Suppose that commercial advertisement can be displayed on BIT screen in this study. And we researched an advertisement rates of the optimum level in using Contingent Valuation Method. In addition, we analyzed a characteristic of user's depending on each time using multinomial Logit Modeling method, and studied for BIT operation and ad. displaying strategy considered user's sex, ages and using times.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.1
• /
• pp.1-6
• /
• 2016

Ensuring the secure operation of power systems has become an important and critical matter during the present time, along with the development of large, complex and load-increasing systems. Security constraints such as the thermal limits of transmission lines and bus-voltage limits must be satisfied under all of a system’s operational conditions. An alternative solution to improve the security of a power system is the employment of Flexible Alternating-Current Transmission Systems (FACTS). FACTS devices can reduce the flows of heavily loaded lines, maintain the bus voltages at desired levels, and improve the stability of a power network. The Unified Power Flow Controller (UPFC) is a versatile FACTS device that can independently or simultaneously control the active power, the reactive power and the bus voltage; however, to achieve such functionality, it is very important to determine the optimal location of the UPFC device, with the appropriate parameter setting, in the power system. In this paper, a genetic algorithm (GA) method is applied to determine the optimal location of the UPFC device in a network for the enhancement of the power-system loadability and the minimization of the active power loss in the transmission line. To verify our approach, simulations were performed on the IEEE 14 Bus, 30 Bus, and 57 Bus test systems. The proposed work was implemented in the MATLAB platform.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2348-2356
• /
• 2011

In recent years, many researches for DC power distributed system (PDS) are being preformed and the importance of the DC PDS is more and more emphasized. Furthermore, in the railway system, the DC PDS is used in subway station lighting, facilities, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple parallel loads such as pulsed power load, motor drive system, and constant power loads. Thus, good quality and high reliability for electric power are required and voltage bus conditioner (VBC) may be used the DC PDS. The VBC is a DC/DC converter for mitigation of the bus transients. In this paper, adaptive controller is designed. The simulation results by PSIM are presented for validating the proposed control algorithm.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.347-350
• /
• 2004

The objective of this study is to discuss the future trend of the community bus. In doing so, we have selected Nagasaki City of Japan. Geographic Information Systems (GIS) is used for selection of the routes. In the present study we are going to add new parameters and new selection method. As a result of the study, we have been able to identify some best possible and detailed routes for the community bus operation in Nagasaki City, which meets the requirement of the welfare community as well as general passengers.

• Journal of Korean Society of Transportation
• /
• v.23 no.5 s.83
• /
• pp.83-92
• /
• 2005

The purpose of the paper is to analyze an effectiveness before and after implementation of the median arterial bus lanes operation. The paper includes a speed analysis based on the Downs-Thomson Paradox theory, and a reliability analysis based on variance analysis of arrival time. According to the speed analysis, some road sections are now under phase 2 according to the Downs-Thomson Paradox, which is a state in which the bus speeds are greater than the car speeds. In the future it is predicted that cars and buses will reach an equilibrium speed which is in phase 3 of the multi-modal equilibrium theory. According to the reliability analysis of arrival time at each bus stop, in roads of median arterial bus lanes. the variance of arrival time is generally smaller than after the scheme implemented in eight months later.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.11
• /
• pp.2914-2922
• /
• 1997

For FA (factory automation) and ATE (automatic test equipment) in the industrial area, the standard bus needs to increase the system performance of multiprocessor environment. VME(versa module european package format) bus is appropriated to the standard bus but has features of small package and low board density. Beside, the density of board and semiconductor have grown to become significant issues that affect development time, project cost and field diagnostics. To fit this trend, in this paper, we composed Revision C.1 (IEEE std. P1014-1987) of the integrated environment for the main function such as arbitration, interrupt and interface between, VMEbus and several control modules Also the designed, VME system controller is implemented on FPGA that can be located even into slot 1. The control and function modules are coded with VHDL mid-fixed description method and then those operations are verified by simulation. As a result of experiment, we confirmed the most important that is the operation of Bus timer about Bus error signal should occur within $56{\mu}m$, and both control and function modules have the reciprocal operation correctly. Thus, the constructed VHDL library will be able to apply the system based VMEbus and ASIC design.

• Journal of odor and indoor environment
• /
• v.17 no.4
• /
• pp.346-354
• /
• 2018

In this study, the condition of the hazardous materials in the bus was monitored according to the ventilation mode of the air conditioning system during bus service. The bus was surveyed using the indoor air quality measurement method of public transportation vehicles within one year of delivery. We evaluate the $CO_2$ and $PM_{10}$, which are the controlled parameters in buses by the Ministry of Environment, and VOCs and HCHO, the non-controlled parameters. The $PM_{10}$ concentration increased due to outdoor air intake; however the $CO_2$ concentration was found to decrease. In addition, the concentration of VOCs and HCHO was found to decrease due to the forced ventilation system and the outdoor air intake. These results show that the concentration of the other materials except $PM_{10}$ can be changed due to the outside air concentration and forced ventilation system. Therefore, through indoor air quality characteristics of the bus according to air condition system are intended to be used as the basis of an operation manual.

• 한국ITS학회:학술대회논문집
• /
• 2008.11a
• /
• pp.488-492
• /
• 2008