• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.11
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• pp.826-833
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• 1988

In this paper we studied the control of overload which could bring the degradation of performance and threaten the stability of the electronic switching system. In order to get the essential requirement for overload control algorithm, we tried to extract the characteristics of commonly used algorithms by means of simulating overload control alogrithms in numerical stored program control switching model. As the result, we could find that the overload control algorithm which monitored the CPU occupancy had the best call complete rate and good response characteristecs and the algorithm using the offered load as a system state variable had a good grade of service which was represented by a short dial tone delay and 3rd quartile of deal tone delay. however, these control algorithms have no generality and need to get the control parameters by the trial-and-error method. We suggested the guidelines on the design of the overload control algorithm.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.507-512
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• 2005

Railroad transportation system has experienced major changes due to KTX introduction. Kyungbu corridor especially Seoul to Cheonan has line capacity problem and its solution has been a primary concern to researchers and policy decision makers. This study explored pattern of train operation between Seoul and Cheonan after the introduction of KTX in 2004. Both the number of trains and available seat capacity per day have increased but maximum number of trains per specific hour has not been changed much. Demand for train shows that if concentrated in a specific time, so number of trains during the peak hour should be increased. But, it is difficult ? 새 line capacity, so increasing seat capacity per train might be an option. An increase in an avaliable sear should be considered the characteristics of each train lines.

• Journal of KIISE:Software and Applications
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• v.33 no.5
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• pp.489-498
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• 2006

In this paper, we suggested a vehicle classification algorithm using pattern recognition method. At present, Inductive Loop Detector is rarely used for vehicle classification because of its low accuracy. To improve the accuracy, we suggest a new algorithm for Loop Detector using neural networks. In the developed algorithm, the inputs to the neural networks are the variation rate of frequency and occupancy-time. The output is classified vehicles. The developed algorithm was assessed at test sites and the recognition rate was 91.3percent. The results verified that the proposed algorithm improves the vehicle classification accuracy compared to the conventional method based on Loop Detector.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1289-1296
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• 2020

The estimation of radioactivity level is vital for population health risk assessment and geological point of view and can be evaluated as rate of exhalation and source concentration (²²⁶Ra, ²³²Th and ⁴⁰K). The present study deals with the soil samples for investigation of radionuclides content and exhalation rates of radon -thoron gas from different sites in northern Haryana, India. Absorbed dose and associated index estimated in the present study are the measures of environmental radioactivity to inhalation dose. Effective doses received by different tissues and organs by considering different occupancy and conditions are also measured. Exhalation rates of radon and thoron are measured with active scintillation monitors based on alpha spectroscopy namely scintillation radon (SRM) and thoron (STM) monitors respectively. Sample height was optimized before measurement of thoron exhalation rate using STM. Average values of radon and thoron exhalation are found 16.6 ± 0.7 mBqkg^-1h^-1 and 132.1 ± 2.6 mBqm^-2s^-1 respectively. Also, a simple approach was also adopted, to evaluate the thoron exhalation which accomplished a lot of challenges, the results are compared with the data obtained experimentally. The study is useful in the nationwide mapping of radon and thoron exhalation rates for understanding the environmental radioactivity status.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4585-4603
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• 2015

Video streaming services make up a large proportion of Internet traffic on both fixed and mobile access throughout the world. Adaptive streaming allows for dynamical adaptation of the bitrate with varying network conditions, to guarantee the best user experience. Adaptive bitrate algorithms face a significant challenge in correctly estimating the throughput as it varies widely over time. In this paper, we first evaluate the throughput estimation techniques and show that the method that we have used offers stable response to throughput fluctuations while maintaining a stable playback buffer. Then, we propose an adaptive bitrate scheme that intelligently selects the video bitrates based on the estimated throughput and buffer occupancy. We show that the proposed scheme improves viewing experience by achieving a high video rate without taking unnecessary risks and by minimizing the frequency of changes in the video quality. Furthermore, we show that it offers a stable response to short-term fluctuations and responds swiftly to large fluctuations. We evaluate our algorithm for both constant bitrate (CBR) and variable bitrate (VBR) video content by taking into account the segment sizes and show that it significantly improves the quality of video streaming.

• Journal of Digital Convergence
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• v.10 no.3
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• pp.233-240
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• 2012

This study aimed to clarify any factors that may have effect on the appropriateness of hospital admission and hospitalization with the intention of facilitating more efficient occupancy of hospital beds and better medical services in the aspect of their quality, minimizing unnecessary occupancy of beds, and ultimately helping patients requiring acute treatments to use immediately hospitals. This paper selected 154 Stroke patients who left neurology department of one general hospital from March, 1, 2006 to September, 31, 2010 as targets to meet the rate according to medical care security and to see the trend of recent 4 years. As study method, this paper analized medical treatment record with AEP to evaluate the appropriateness of hospital admission and stay and the collected data was computerized through SPSS 12.0. Based upon the results above, the conclusion was drawn that the higher appropriateness of hospital admission and the shorter length of hospital stay will lead to the higher appropriateness of hospitalization. In other words, it is required to provide hospitalized patients with all kinds of behaviors including medical treatments and nursing care service, management of pharmaceuticals, tests, rehabilitation and symptoms, as well as instructions and information for patients. Meanwhile, as it was found that the length of hospital stay may affect the appropriateness of hospitalization, the longer length of hospital stay may result in reduced bed turnover rate. In this light, it is necessary to organize a task force team responsible for evaluation and control of the appropriateness of hospitalization and hospital stay length to improve the quality of medical service in a medical center, so that patients can leave the center timely. Ultimately, governmental supports such as expansion of long-term care facilities will reduce the necessary length of hospital stay so that patients with stroke can receive rehabilitative treatments and long-term care service shortly after completion of acute treatments.

• Journal of Navigation and Port Research
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• v.41 no.3
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• pp.137-148
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• 2017

Port service level is a metric of competitiveness among ports for the operating/managing bodies such as the terminal operation company (TOC), Port Authority, or the government, and is used as an important indicator for shipping companies and freight haulers when selecting a port. Considering the importance of metrics, we developed software to objectively define and manage six important service indicators exclusive to container and bulk terminals including: berth occupancy rate, ship's waiting ratio, berth throughput, number of berths, average number of vessels waiting, and average waiting time. We computed the six service indicators utilizing berth 1 through berth 5 in the container terminals and berth 1 through berth 4 in the bulk terminals. The software model allows easy computation of expected ship's waiting ratio over berth occupancy rate, berth throughput, counts of berth, average number of vessels waiting and average waiting time. Further, the software allows prediction of yearly throughput by utilizing a ship's waiting ratio and other productivity indicators and making calculations based on arrival patterns of ship traffic. As a result, a TOC is able to make strategic decisions on the trade-offs in the optimal operating level of the facility with better predictors of the service factors (ship's waiting ratio) and productivity factors (yearly throughput). Successful implementation of the software would attract more shipping companies and shippers and maximize TOC profits.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.4
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• pp.106-118
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• 2002

In recent years, synthetic and systematic management with conservation-oriented strategy for Baekdu-daegan, which is the greatest chine as well as the major ecological axis of the Korean Peninsula, is being required to cope adequately with the various kinds of developmental urge. For this, spatially definite zoning for the managerial area on Baekdu-daegan has to be completed first. This study is to take into consideration the traditional concepts of stream and watershed as well as the actual disturbance on Daegan area, and to propose the process for reasonably establishing the managerial boundary adjacent to the Ridges. The case site with topographically diverse characteristics was selected, and the analyses on watershed, road network and land use were carried out using the digital maps and Landsat TM images. Based on these analyses results, the managerial boundaries as alternatives from the Ridges were produced by watershed expansion process, and used for tracing the changes of road occupancy rate and the areal ratio of various land use types to the relevant watersheds to search out the adequate managerial boundary. The results show that watershed expansion process could be effective tool for establishing the managerial boundary, and the fourth expanded watershed would be included for the adequate managerial boundary of the case site.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.2070-2086
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• 2014

As a kind of personal lifelog data, activity data have been considered as one of the most compelling information to understand the user's habits and to calibrate diagnoses. In this paper, we proposed a robust algorithm to sampling rates for human activity recognition, which identifies a user's activity using accelerations from a triaxial accelerometer in a smartphone. Although a high sampling rate is required for high accuracy, it is not desirable for actual smartphone usage, battery consumption, or storage occupancy. Activity recognitions with well-known algorithms, including MLP, C4.5, or SVM, suffer from a loss of accuracy when a sampling rate of accelerometers decreases. Thus, we start from particle swarm optimization (PSO), which has relatively better tolerance to declines in sampling rates, and we propose PSO with an adaptive boundary correction (ABC) approach. PSO with ABC is tolerant of various sampling rate in that it identifies all data by adjusting the classification boundaries of each activity. The experimental results show that PSO with ABC has better tolerance to changes of sampling rates of an accelerometer than PSO without ABC and other methods. In particular, PSO with ABC is 6%, 25%, and 35% better than PSO without ABC for sitting, standing, and walking, respectively, at a sampling period of 32 seconds. PSO with ABC is the only algorithm that guarantees at least 80% accuracy for every activity at a sampling period of smaller than or equal to 8 seconds.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.229-239
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• 2008

Most algorithms for detecting incidents have been developed under the premise that congestion must happen whenever an incident occurs. For that reason, the performance of these algorithms could not be guaranteed in cases where congestion did not happen due to traffic operations with low flows despite the occurrence of an incident. The objective of this paper is to develop an automatic incident detection algorithm using a new diagram that can reliably detect the incident under various conditions of traffic operations including a low volume state. Compared with the McMaster Algorithm, the proposed algorithm in this paper was evaluated with three different cases in which the incidents occur in traffic operations with a low volume state, a relatively high volume state, and a recurrent congestion state. It is shown that the new algorithm has a capability to identify the flow characteristics of incidents for all the three cases and is much better than McMaster algorithm in terms of detection rate and false alarm rate.