• Proceedings of the KIEE Conference
• /
• 2005.10c
• /
• pp.273-275
• /
• 2005

The national need to establish a new stray current mitigation method to protect the underground metallic infrastructures in congested downtown area forced us to design and develop the distributed impressed current cathodic protection (DICCP) system. The main purpose of this system is to replace the stray current drainage bond methods, which is widely adopted by pipeline owners in Korea. Currently, forced drainage makes up about 85% of total drainage facilities installed in Korea because polarized drainage can neither drain perfectly the stray currents during normal operation of electric vehicle nor drain the reverse current during regenerative braking at all. The forced drainage, however, has been abused as an alternative cathodic protection system, which impresses currents from rails to the pipelines and accordingly uses the rails as anodes. As a result, it is necessary to consider a new method to both cathodically protect the pipelines and effectively drain the stray currents. In this paper, we describe the design parameters and installation schemes of DICCP system that can meet these demands.

• Korean Journal of Geomatics
• /
• v.2 no.1
• /
• pp.65-73
• /
• 2002

GPS in the United States and GLONASS of the old Soviet Union are used currently as satellite navigation systems. Plans are being made to use the Galileo satellite system in Europe, and these plans focus on a combined application of the satellite navigation systems. In this study, we examined the possibility of effective application of a combination of GPS/GLONASS in urban areas, where 3-dimensional positioning is impossible with GPS alone. We analyzed the 3-D coordinate deviation of a GLONASS satellite by integration interval and compared it with GLONASS satellite coordinates in precise ephmerides by transforming it into WGS84. We also programmed GPS/GLONASS, analyzed 3-D positioning accuracy by static surveying and kinematic surveying with Ashtech Z18 receivers and Legacy receivers, and then compared the results to those of GPS surveying. As a result, we are able to decide the integration interval for producing GLONASS satellite coordinates in navigation and geographical information and construct a GPS/GLONASS data processing system by developing a DGPS/DGLONASS positioning program. If more than four GLONASS satellites are observed, the accuracy of GPS/GLONASS is better than that of GPS positioning. As a result of kinematic surveying in a congested urban area with skyscrapers, we discovered that the GPS/LONASS combination is very effective.

• Journal of the Institute of Convergence Signal Processing
• /
• v.22 no.1
• /
• pp.38-44
• /
• 2021

Wi-Fi provides some low-power connection solutions that other Bluetooth cannot provide, and at the same time brings many benefits. First, there is a potentially higher data rate: it can reach 230mbps. Wi-Fi coverage is also wider than competitors, and its operating frequency is also 5GHz, which is much less congested than 2.4GHz. Finally, it also supports IP networks, which is important if you want to send data to the cloud without complexity. The 802.11ac standard of the previous generation still accounts for most shipments (80.9%) and revenue (76.2%). However, there is a limit to accepting IoT devices that will continue to increase significantly in the future. To solve this problem, the new Wi-Fi 6 standard is expected to be the solution (IEEE 802.11ax) which is quickly becoming the main driving force of the wireless local area network (WLAN) market. According to IDC market research analysts, in the first quarter of 2020, independent access points (APs) supported by Wi-Fi 6 accounted for 11.8% of shipments, but 21.8% of revenue. In this paper, we have compared and analyzed the IoT connectivity, QoS, and security requirements of devices using Wi-Fi 6 network.

• Journal of the Korean Professional Engineers Association
• /
• v.16 no.1
• /
• pp.20-34
• /
• 1983

A phenomenon in the unplanned urban sprawl of Cheong-ju city has to be rest-rained from disposing and to develop, though progress in urbanization inevitably decreases rural area. So, this thesis aims at reviewing, revising and guiding toward the more effective land use planning practice and zoning mechanism and system of Cheong-ju city. I proposed that land use planning should be had several factors and thereupon that Korean zoning mechanism and system including Building Code should be amended because of inducing human activities in buildings and facilities not to demarcate and plan every one of them. First, the factors of urban planning are a rather diversified approach to it than a unified, supplementation of the applicable difference in time between preparing and appling it, a solid controlling system, a micro and macro planning theory and giving serious consideration for the inertia from the existing land use. Second, the applicable amendments for our zoning mechanism including Eluding Code are as follows; a need of reorganization for Zoning Ordinance appricated to different regulation concerning a scale and peculiarity of a oily, a decision of the different earmarked confinement in area to different zone ana from Zoning Ordinance in City Planning Law, a demarcated facilities and the more detailed land use concerning human activies than the exsisting and entrusting decision on the ways and processes of it to every rural city planning committee, a settlement of zone ana area considering for block-unit and Planned Unit Development(P. U. D.), and a need of security jurisprudence in order to solve the zoning regulation rather in City Planning Law than in Building Code that our zoning regulation and controlling system are depended on. According to these applicable amendments to Cheong-ju city, I proposed the conceptions of Cheong-ju city land use planning are as follows; a reinforcement with one cored pattern of urban land use, a selection of gradual urban sprawl by way of city development and renewal, a strengthening accessibility to the core of the city with Plurizing the system of arterial roads, a choice of priority to conservation at the core of tile city and security of open spaces and parking area at the area of the city, a harmonization between development and conservation at the inner ring area that is situated between the core and periphery reserved area in order to develop in the future, a buffered open space situated at the congested area with heterogenous functions, and a completion of urban open space system. The proposal made here so far is for the hope of the better structure of Cheong-ju city that should be granted to the peculiarity developed with educational, cultural, conservative and self-sufficient city functions.

• Journal of Korean Society of Transportation
• /
• v.24 no.7 s.93
• /
• pp.115-128
• /
• 2006

The analytic methodology of a merging area in KHCM(2004) supposes that congestion nay occur when traffic demand is more than capacity However, in many cases, congestion on merging area occurs when summation of traffic demand of main line and ramp is less than capacity, and in present methodology analysis of how main line and ramp flow effect on congestion occurrence is difficult. In this study, the model that is able to estimate traffic flow condition on merging area in accordance with the combination of main line and ramp demand flow is developed. Main characteristic of the model is estimation of maximum possible throughput rate and maximum throughput rate according to the combination of main line and ramp demand flow. Through the estimation of maximum possible throughput rate and maximum throughput rate. it was Possible to predict whether congestion would occur or not and how much maximum throughput rate and congestion would be on merging area. On one hand, in present LOS evaluation methodology on merging area, congestion state is determined as un-congested flow if demand flow is less than capacity. Therefore, to establish more reasonable In evaluation method, new criterion of LOS evaluation on merging area was searched based on the model of this study.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.5
• /
• pp.106-114
• /
• 2015

Wireless Body Area Network(WBAN) is a network standard around a human body which connects various medical sensor and devices It has to satisfy various demands such as data transmission rate, priority, and delay time. In this paper, considering a data priority and transmission delay time, is proposed to improve efficiency of WBAN service depending on congestion status of network. The proposed algorithm operates with adapted data removal probability according to data priority when the hub buffer is congested than before. And in the case of lower congestion within the hub buffer data is served considering data delay time. Through the comparison with other existing scheduling algorithms, it is confirmed that quality of WBAN service is improved due to lower data loss rate of medical data and less delay time in the proposed algorithm.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.17 no.3
• /
• pp.116-131
• /
• 2014

In this study, sunshine environment in an urban area is analyzed using a numerical model which considers sunshine-duration blocking by topography and buildings. The numerical model used in this study has an improvement in the algorithm detecting sunshine duration in the model domain. The main improvement in the algorithm is to detect sunshine duration using all the surfaces of any grid cell(the previous model uses the center of any grid cell). The improvement in the algorithm gives more accurate evaluation of sunshine duration at corner surfaces of buildings. Using the improvement model and geographic information system(GIS) data, sunshine environment is analysed at an building-congested area in Busan for a week in four seasons. The results show that sunshine duration can be much changed by apartment complexes, high-rise buildings, topography in the model domain.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.11
• /
• pp.973-980
• /
• 2016

An air traffic management (ATM) has been studied in a variety of fields to utilize an air traffic capacity efficiently and solve a congested air traffic situation due to an increment of an air traffic demand. In this paper, an air traffic management, which is related with controlling and determining the sequencing of an aircraft approaching to an airport, in terminal control area is studied. This paper focuses on scheduling algorithms with a given problem for the air traffic management with operational constraints, such as a space separation, an overtaking on the same air-route, and a route merge point (a scheduling point). For a real-time calculation, the presented algorithms focus on dispatching heuristic rules which are able to assign tasks in a fast time period with an adequate performance, which can be demonstrated as a proper and realistic scheduling algorithm. A simulation result is presented to illustrate the validity and applicability of the proposed algorithm. Each scheduling rule is analyzed on the same static and dynamic air traffic flow scenario with the ATM Monte-Carlo simulation.

• Journal of the Korean Institute of Navigation
• /
• v.12 no.2
• /
• pp.43-55
• /
• 1988

The amount of cargoes and fishery production have increased continuously during the last decade due to the great growth of the Korean economy. These increasements have made our coastal traffic congested, and the future coastal traffic is also expected to increase considerably. The increased traffic can be a cause of large sea pollution as well a s greater sea casualties us as properties and human lives, which could result in a big national loss. In order to prevent the sea casualties and promote the safety of coastal traffic, the Vessel Traffic Management System (VTMS) along the Korean coastal waterway is inevitably introduced. But, the precise evaluation is necessary required prior to the implementation of VTMS because this system necessitates a huge amount of budgets. This paper aims to propose the model of evaluation process, but the evaluation as to the urgency of establishment is not only very complicated and fuzzy but also affected by the subjectivity of human. Therefore, fuzzy integral is adopted as the mathematical model of evaluation in which decision-maker can intervence by making decision considering the calculated membership-function. Four aspects, namely, the frequency of sea-casualities, the traffic volume, the frequency fuzzy day, and the complexity of waterway are selected as the item of evaluation, and the fuzzy measure are applied to the evaluation of 8 candidated regions such as the adjacent area to the port Inchen, Kunsan, Mokpo, Wando, Yosu, Pusan, Pohang, Donghae. As a result of evaluation, the priority as to the candidated regions is obtained, and the following prior execution regions, namely, the adjacent area to the port Pusan, Yosu, Mokpo & Wando are selected by considering the present situation, but, in the long run, the VTMS should be executed in the whole coast of the nation, through the cost-effectiveness analysis.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.18 no.6
• /
• pp.137-154
• /
• 2019

This study analysed the center control emergency vehicle preemption[EVP] test result on the 1.782 km section around Gangbuk Fire Station. The pros and cons between center control and site control EVP was compared through the review of existing research. The test site was selected based on the higher link speed for choosing low congested area and 4 to 6 lane road. EVP operates green extension under the estimated arrival time to each intersection. This study is about EVP system field application and its evaluation by analyzing EVP operation result with the emergency vehicle's trace, GPS data. The impact on the surrounding traffic was analysed in delay from the queue length survey. Analysis showed the decrease in averge travel time 41.81%, but the increase in delay of surrounding traffic slightly. It is expected that EVP can be applied to the expanded area by researching EVP compensation scheme.