• Journal of Korean Society of Transportation
• /
• v.24 no.1 s.87
• /
• pp.109-120
• /
• 2006

Since the 1st of July, 2004, the public transport system of the Seoul metropolitan area has been rearranged. In the new system, bus lines are divided into 4 classes-wide area, arterial road, branch, and rotation lines with renewed fare system based on the total distance travelled. Since central control center known as the Bus Management System (BMS) integrates the entire system operation. it now becomes feasible to collect travel information and provide it to the users scientifically and systematically. The Purpose of this study is to forecast transit travel time using real-time traffic data coming from both buses and subway. This is significant contribution since provision of real-time transit information and easy access to it would most likely boost the use of mass transit system, alleviating roadway congestion in the metropolitan area.

• Korean Journal of Construction Engineering and Management
• /
• v.7 no.6
• /
• pp.79-89
• /
• 2006

Current removing process is labor intensive and time consuming, employing a conventional grinding type manual machine. From a social and economic point of views, these kinds of manual tasks bring about social inconvenience and economic loss including traffic jam and high labor costs. The objective of the study was to develop and evaluate a road stripe removal equipment using water jet technology. The following shows the results. First, It was analyzed that the obtainable productivity from the equipment developed in the study is 280% compared to the current equipment. In this study, it was also calculated the Benefit/Cost Ratio and the result showed that the ratio is 3.28, so it is expected that the equipment can produce great benefits for the relevant companies. Second, an analysis was also conducted on the traffic congestion cost, and the equipment could save about \2,550 million per day compared to the conventional equipment. Therefore, it is analyzed that the economic viability of the equipment is sufficient.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.41 no.2
• /
• pp.53-65
• /
• 2016

Static wireless multi-hop networks, such as wireless mesh networks and wireless sensor networks have proliferated in recent years because of they are easy to deploy and have low installation cost. Two key measures are used to evaluate the performance of a multicast tree algorithm or protocol : end-to-end delay and the number of transmissions. End-to-end delay is the most important measure in terms of QoS because it affects the total throughput in wireless networks. Delay is similar to the hop count or path length from the source to each destination and is directly related to packet success ratio. In wireless networks, each node uses the air medium to transmit data, and thus, bandwidth consumption is related to the number of transmission nodes. A network has many transmitting nodes, which will cause many collisions and queues because of congestion. In this paper, we optimize two metrics through a guaranteed delay scheme. We provide an integer linear programming formulation to minimize the number of transmissions with a guaranteed hop count and preprocessing to solve the aforementioned problem. We extend this scheme not only with the guaranteed minimum hop count, but also with one or more guaranteed delay bounds to compromise two key metrics. We also provide an explanation of the proposed heuristic algorithm and show its performance and results.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.3
• /
• pp.39-49
• /
• 2010

Ad hoc network is infrastructureless network, that the network topology is configured by each node. Each node capacity device function namely, accomplishes a network control and a function of management because not being Network device of the exclusively. Ad hoc networks what kind of node join or leave the network topology to facilitate the expansion of arbitrary topology, to the case which is the distance whose traffic is distant the place must overtake through the route of intermediate nodes, like these facts give an effect to performance fluctuation. Consequently, each node in order to maintain traffic of oneself stably there is a necessity which will consider traffic and congestion control from the node which traffic of a condition and oneself of traffic of the circumference and the route which compose the network will overtake through. This paper assumes the path of the band with a finite resource, and path traffic to occupy the competition and its impact on transmission performance of these competing arguments to configure the model factor to analyse the performance impact on the results presented. Like this result with the fact that from the study, it will contribute in network management policy and the technique.

• Journal of the Society of Disaster Information
• /
• v.3 no.1
• /
• pp.55-68
• /
• 2007

Recently, people in cities of developed countries are exposed to unfortified damages of crime and disaster due to urbanization, industrialization and information-oriented era caused by congestion of population in terms of hardware and various social pathology phenomena and frequent and large scale of disaster caused by crime and disorder, which occur in the course of going through nuclear family, a gap between rich and poor and aging society in terms of software. In this regard, demand for security upon individual life and property has been increased but the police that are responsible for the public security does not effectively reduce damage in life and property because their activities are mainly oriented in coping with security accidents more than prevention. Shortage of manpower and budget, retarded equipment, and heavy overwork are the reasons. In order to confront with this kind of situation, we should utilize CCTV system with the purpose of declining possible chances of crime, not for eliminating cause of crime as crime prevention activities to predict danger in advance as a way of prevention and we may expect a role of damage prevention by installing CCTV in places where security accident may possibly happen. In conclusion, there are invasion of privacy, misuse of the system, insufficiency of overall monitoring office management, lack of citizens' understanding and economical allotment of the system installation costs in installation of CCTV system. However. it is necessary to install the CCTV system for effective prevention of crime and prevention activities of security accidents and accurate PR of purposes of installing CCTV to local residents, establishing relevant laws about system misuse, allotment of equipment costs and fees by R&D of the system machinery, cost reduction method of storage, management and replacement, saving costs from co-operative attitude of government, and local autonomous entities and local residents should be involved.

• Journal of Navigation and Port Research
• /
• v.32 no.3
• /
• pp.159-165
• /
• 2008

The coastal shipping transport for containers had been serviced by Hanjin Transpotation Co., Ltd. and Korea Express Co., Ltd. from 1995. But Korea Express Co., Ltd. and Hanjin Transpotation Co., Ltd had stopped a coastal shipping transport service routed Busan-Incheon bemuse of getting worse of operation balance in 1999 and 2006 respectively. As a result of these situations, korean-flag and foreign-flag fleets are having difficulty in handling T/S cargos and in-time transport service among inter-ports in korea. As shippers also use lorry to transport their cargos than using costal shipping, it occurs increasing in national logistics' cost as well as time-consuming due to congestion on the road. Therefore, this paper identifies not anly current costal shipping transport systems but also those problems and analyses a economic effect in case of participation in the costal shipping transport service by foreign-flag vessel using monte carlo simulation.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.40 no.2
• /
• pp.13-21
• /
• 2017

Airline schedules are highly dependent on various factors of uncertainties such as unfavorable weather conditions, mechanical problems, natural disaster, airport congestion, and strikes. If the schedules are not properly managed to cope with such disturbances, the operational cost and performance are severely affected by the delays, cancelations, and so forth. This is described as a disruption. When the disruption occurs, the airline requires the feasible recovery plan returning to the normal operations in a timely manner so as to minimize the cost and impact of disruptions. In this research, an Ant Colony Optimization (ACO) algorithm with re-timing strategy is developed to solve the recovery problem for both aircraft and passenger. The problem consists of creating new aircraft routes and passenger itineraries to produce a feasible schedule during a recovery period. The suggested algorithm is based on an existing ACO algorithm that aims to reflect all the downstream effects by considering the passenger recovery cost as a part of the objective function value. This algorithm is complemented by re-timing strategy to effectively manage the disrupted passengers by allowing delays even on some of undisrupted flights. The delays no more than 15 minutes are accepted, which does not influence on the on-time performance of the airlines. The suggested method is tested on the real data sets from 2009 ROADEF Challenge, and the computational results are compared with the existing ones on the same data sets. The method generates the solution for most of problem set in 10 minutes, and the result generated by re-timing strategy is discussed for its impact.

• Journal of the Korean Society of Safety
• /
• v.27 no.3
• /
• pp.153-160
• /
• 2012

Various social problems such as traffic congestion, car accidents and environmental problems(air pollution, noises etc.) have been happening in the Seoul metropolitan area that has the car oriented traffic system providing cars continuously. Along with this, the financial burden caused by current oil price anxiety made paradigm shift from caroriented to public transportation-oriented. Its typical example is an arterial branch bus system changing(bus lane through the center of main road) started in Seoul in July, 2004. But study on safety analysis of bus lane and characteristic of accidents are not sufficient enough to now. The bus lanes are expanded to provide roads for better traffic operation and accidents between buses and pedestrians or ordinary vehicles are considered main problems. This study divided each bus route of median bus lane(bus-only lane through the center of main roads) and bus lane at roadside by intersection and collected and analysed data about influence variables of bus accidents chosen in each section. We constructed a logistic model using collected data. As a result, bus lane at roadside are used by both buses and other kinds of vehicles differently from median bus lane and showed such characteristic in accident influence. Therefore access management to factors causing conflict and improvement of operation management are required. In case of median bus lane, the more buses moving general vehicle lane and traffic volume of section were, the more accidents happened. In case that stop line of center lane is not backward, view blocking of vehicles turning left caused accidents.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.27 no.4
• /
• pp.101-109
• /
• 2014

Objective : The purpose of this study is to summarize the differential diagnosis between allergic and nonallergic rhinitis and suggest management. Methods : We reviewed the current update of medical history and physical examination for allergic and nonallergic rhinitis. Then we analyzed clinical characteristics according to onset age, gender incidence and state of nasal symptoms, etc. Results : 1. Patients with nonallergic rhinitis tend to develop symptoms at a later age(>35 years of age), and there is a female-to-male incidence ratio for nonallergic rhinitis of 2:1 to 3:1. 2. Patients with nonallergic rhinitis report nasal congestion, nasal rhinorrhea and more often report postnasal drip rather than sneezing and itching, which are predominant symptoms of allergic rhinitis. And the nasal mucosa in nonallergic rhinitis usually looks normal. 3. Patients with nonallergic rhinitis have few complaints of concomitant symptoms of allergic symptoms and the absence of other atopic diseases in the patient or in the family supports the diagnosis of nonallergic rhinitis. 4. Common triggers of nonallergic rhinitis are nonspecific irritant exposures and many patients with nonallergic rhinitis find that antihistamines have no benefit. Conclusions : The differential diagnosis between allergic and nonallergic rhinitis is clinical and relies on a detailed medical history and physical examination.

• Journal of Digital Convergence
• /
• v.17 no.1
• /
• pp.169-177
• /
• 2019

The city is experiencing various problems such as traffic congestion, environmental pollution, urban crime, and faces the limit of growth. Recently, various attempts to build a Smart City have been spreading around the world, in order to solve these problems. Smart City is attracting attention as the core platform of the future city with the $4^{th}$ industrial revolution. However, various definitions of smart city are mixed, and the methods and strategies for implementing smart city are changing or evolving due to the development of technology and the experience during that time. This study summarizes the definition of various smart city through literature review and suggests smart city building strategy that enables sustainable growth of cities as a platform of the $4^{th}$ industrial revolution era.