• Journal of Information Technology Services
• /
• v.12 no.1
• /
• pp.1-14
• /
• 2013

The government has implemented operating the bus information terminal (hereinafter, 'BIT') to use by building it at a major bus station to solve the problem of traffic congestion. Busan Metropolitan City has been continuously expanding the installation of 'BIT' since 2003. However, there are few research on the factor to use and satisfaction survey on 'BIT' from the perspective of the users. This study, in an effort to inquire into the 'BIT' utilization factor and its vitalization plan, conducted a face to face survey of 172 citizens who had the experience in the 'BIT'. The result of the data analysis showed that usability, convenience, and availability were the critical factors for a BIT use. In addition, the general intention to use 'BIT' was found to be very high as much as 90.7%. The contributions of this study are as follows. The academic contributions is that it proved the relationship between usability, convenience and the intention to use suggested by the information technology acceptance model is supported even in case of 'BIT.' For the practitioners this study provides ground data for a local government to make a plan of a BIT extension.

• Journal of Power Electronics
• /
• v.16 no.6
• /
• pp.2315-2326
• /
• 2016

This paper discusses the elimination of DC voltage deviation and the enhancement of load current sharing accuracy in multi-terminal high voltage direct current (MT-HVDC) systems. In order to minimize the power line losses in different parallel network topologies and to insure the stable operation of systems, a decentralized control method based on a modified droop control is presented in this paper. Averaging the DC output voltage and averaging the output current of two neighboring converters are employed to reduce the congestion of the communication network in a control system, and the decentralized control method is implemented. By minimizing the power loss of the cable, the optimal load current sharing proportion is derived in order to achieve rational current sharing among different converters. The validity of the proposed method using a low bandwidth communication (LBC) network for different topologies is verified. The influence of the parameters of the power cable on the control system stability is analyzed in detail. Finally, transient response simulations and experiments are performed to demonstrate the feasibility of the proposed control strategy for a MT-HVDC system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2018.05a
• /
• pp.228-229
• /
• 2018

To deal with the increasing volume of the vessel's cargo in the container flow and the enlargement trend of the vessels, Pusan port is making efforts from various perspectives such as the creation of global infrastructure and the promotion and development of new wharves. If Pusan port can provide and prepare the eligible infrastructures for future berthing of larger vessels. It will be able to operate with vessels larger than 20,000TEU, and it will also be able to grow into one of the main port of the Mega max era.. However, when large vessels dock, many berths, equipment, working time and labors are required. As a result, the problem of delaying time of other consecutive vessels will inevitably arise. In response to this, we analyze the impact and effect of the birthing of a large vessel on other congestion vessels at a container terminal.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.6
• /
• pp.117-122
• /
• 2022

In this paper, we developed a vehicle control terminal using IoT and low-power long-distance communication (NB-IoT) technology. This system collects information on the location and status of a parked vehicle, and transmits the vehicle status to the vehicle owner's terminal in real time with low power to prevent vehicle theft, and in the case of a vehicle in motion, When primary information about the vehicle, such as an impact, is collected and transmitted to the server, the server analyzes the relevant data to generate secondary information on traffic congestion, road damage, and safety accidents. By sending it, you can know the exact arrival time of the vehicle at its destination. This terminal device is an IoT gateway for a vehicle and can be connected to various wired and wireless sensors inside the vehicle. In addition, the data collected from vehicle maintenance, efficient operation, and vehicles can be usefully used in the private or public sector.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.06a
• /
• pp.385-386
• /
• 2022

Currently, global developed countries in shipping and logistics establish smart ports by introducing various digital technologies such as automated terminals and sharing platforms. This means that the importance of efficiency throughout the port by improving resource utilization efficiency and minimizing work idle time is increasing. Therefore, this study proposes a yard truck dispatching method of improving resource utilization efficiency. And we analyze the problems of the existing dispatching rules and develop Y/T dispatching algorithm that comprehensively considers related constraints. In addition, the simulation takes into account the terminal congestion based on the operation data of the Busan New Port, it is conducted using the existing dispatch method and developed Y/T dispatching algorithm. And the operational effects of analysis result are evaluated.

• Journal of Navigation and Port Research
• /
• v.48 no.1
• /
• pp.27-33
• /
• 2024

Following the COVID-19 pandemic, congestion within container terminals has led to a significant increase in waiting time and turnaround time for external trucks, resulting in a severe inefficiency in gate-in and gate-out operations. In response, port authorities have implemented a Vehicle Booking System (VBS) for external trucks. It is currently in a pilot operation. However, due to issues such as information sharing among stakeholders and lukewarm participation from container transport entities, its improvement effects are not pronounced. Therefore, this study proposed a deep learning-based predictive model for external trucks turnaround time as a foundational dataset for addressing problems of waiting time for external trucks' turnaround time. We experimented with the presented predictive model using actual operational data from a container terminal, verifying its predictive accuracy by comparing it with real data. Results confirmed that the proposed predictive model exhibited a high level of accuracy in its predictions.

• Journal of Navigation and Port Research
• /
• v.40 no.1
• /
• pp.35-41
• /
• 2016

Port congestion has been recognized as one of the critical factors for port service competitiveness and port selection criteria. However, congestion ratio, the congestion index currently used by Korea, plays a very limited role in shipping companies' and shippers' selection of port and port authorities' decision making regarding port management and development. This is mainly due to the fact that this ratio is only calculated as the ratio of the number of vessels by each port. Therefore, this study aims to measure service level related to vessel entry and departure in Korea ports by evaluating waiting ratio(WR) according to terminals and vessel types. The results demonstrate that the waiting ratio of containerships and non-containerships is less than 4% and 15% respectively, which satisfies the reasonable level suggested by the UNCTAD and OECD. Port of Pohang is revealed to have the highest WR of 57% and among the terminals, No. 1 Terminal of the Shinhang area has the highest WR. In terms of ship types, WR of Steel Product Carrier is highest, followed by General Cargo Ship and Bulk Carrier at the Pohang Shinhang area. In addition to WR, berth occupancy ratio as well as the number and time of waiting vessels can be utilized to evaluate service level by ports and terminals from port users' perspective, and furthermore, to improve the port management and development policy for port managers or authorities.

• Journal of the military operations research society of Korea
• /
• v.18 no.2
• /
• pp.126-139
• /
• 1992

In this paper, the computational problems of packet transmission probability (PTP) in a computer communication network (CCN) under flooding routing are investigated. To avoid a congestion under this routing, two control methods are considerd, i. e., copy storage control and hop count control. Problems of PTP under flooding routings with these two control methods are respectively shown to be equivalent to those of source-to-terminal reliability(STR) with an exception for a case of hop count control where the hop count is less than the length of the longest path. For this exceptional case, an efficient computational algorithm for PTP is developed. This algorithm is proposed as an efficient tool for the determination of hop count which satisfies a given reliability constraint. A numerical example illustrates a proposed algorithm.

• Proceedings of the KIEE Conference
• /
• 1998.07g
• /
• pp.2390-2392
• /
• 1998

In this paper, we discuss the development of monitoring system with data process equipment which transfers data from Remote Terminal Unit(RTU) to monitoring computer. The RTUs sense temperature, pressure and PLC(Programmable Logic Controller) nodes conditions of scrubber in semiconductor manufacture processing. The data Process equipment is connected every RTU and a monitoring computer through serial communication. This equipment receives informations from RTU, process data, and transfers them to monitoring computer. To avoid congestion in data communication, task scheduling algorithm used RT O/S(Real-Time Operating System) is embedded in ROM which is a part of data Process equipment.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.3
• /
• pp.48-55
• /
• 2015

This paper studies how to solve a problem caused by M2M terminals sending a few data based on $3^{rd}$ Generation Partnership Project(3GPP) Long Term Evolution-Advanced(LTE-A) system and then it is analyzed, proposed, and introduced into the techniques. Especially, it is introduced solution for the lack of Random Access Channel and an increasing number of latency caused by countless M2M devices. It is proposed the technology for M2M grouping as well as allowable access probability according to user type. As it decreases the number of terminal by grouping M2M devices to try random access at PRACH, it can be reduced collision between Cellular users and M2M devices. So, it is proved that the proposed mechanism can solve the increasing average latency of random access on system coexisting Cellular users and M2M devices through simulations.