• Journal of Korea Port Economic Association
• /
• v.37 no.1
• /
• pp.179-196
• /
• 2021

Port congestion rate at Busan Port has increased for three years. Port congestion causes container reconditioning, which increases the dockyard labor's work intensity and ship owner's waiting time. If congestion is prolonged, it can cause a drop in port service levels. Therefore, this study proposed an anomaly detection method using ARIMA(Autoregressive Integrated Moving Average) model with the daily volume data from 2013 to 2020. Most of the research that predicts port volume is mainly focusing on long-term forecasting. Furthermore, studies suggesting methods to utilize demand forecasting in terms of port operations are hard to find. Therefore, this study proposes a way to use daily demand forecasting for port anomaly detection to solve the congestion problem at Busan port.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.43 no.4
• /
• pp.1-14
• /
• 2020

Recently, M/G/1 priority queues with a finite buffer for high-priority customers and an infinite buffer for low-priority customers have applied to the analysis of communication systems with two heterogeneous traffics : delay-sensitive traffic and loss-sensitive traffic. However, these studies are limited to M/G/1 priority queues with finite and infinite buffers under a work-conserving priority discipline such as the nonpreemptive or preemptive resume priority discipline. In many situations, if a service is preempted, then the preempted service should be completely repeated when the server is available for it. This study extends the previous studies to M/G/1 priority queues with finite and infinite buffers under the preemptive repeat-different and preemptive repeat-identical priority disciplines. We derive the loss probability of high-priority customers and the waiting time distributions of high- and low-priority customers. In order to do this, we utilize the delay cycle analysis of finite-buffer M/G/1/K queues, which has been recently developed for the analysis of M/G/1 priority queues with finite and infinite buffers, and combine it with the analysis of the service time structure of a low-priority customer for the preemptive-repeat and preemptive-identical priority disciplines. We also present numerical examples to explore the impact of the size of the finite buffer and the arrival rates and service distributions of both classes on the system performance for various preemptive priority disciplines.

• Journal of Korea Multimedia Society
• /
• v.6 no.7
• /
• pp.1256-1265
• /
• 2003

Content Delivery Network(CDN) is a mechanism to deliver multimedia content to end users on behalf of web content providers. Provider's content is distributed from content server to a set of delivery platforms located at Internet Service Providers(ISPs) through the CDN in order to realize better performance and availability than the system of centralized provider's servers. Existing work on CDN has primarily focused on techniques for efficiently multicasting the content from content server to the delivery platforms or to end users. Multimedia contents usually require broader bandwidth and accordingly WDM broadcast network has been highly recommended for the infrastructure network of CDN. In this paper, we propose methods for partitioning a multicast group into smaller subgroups using the previous status of receivers. Through the computer simulation, we show that proposed algorithm are useful to reduce the average receiver's waiting time and the number of transmissions.

• Korean Journal of Digital Imaging in Medicine
• /
• v.8 no.1
• /
• pp.21-26
• /
• 2006

Hospitals these days are trying to introduce the a practice has recently been generalized in the test or diagnosis process, where test results and images from different test labs are interlinked together. This process is identical to that of physical aspect in EMR process, which computerizes the paper results within the hospital. One of the prerequisites for the process of computerizing test results is the interface between clinical test devices in the test labs. However, due to the variety of prescription inputs, disparity of test result papers, complexity of job in test labs and diversify of interfaces among the different devices, interconnection with the hospital information system is a complicated job. A universal control of clinical test devices which have independent communication protocols has become possible by connecting them with an interface workstation. As for the patients, waiting time for test has been reduced, and, thanks to the synchronized result retrieval system, it has become possible to check the test results on the very day of the test. As a result, the length of hospitalization has been reduced, too. In terms of workflow, as the transfer of charts and transfer of result papers are separated, the embarrassing job of collecting result papers has disappeared. As patients' test appointment and the results processing can be made on-line, extra work for doctors have disappeared. And, thanks to the computerization of test results information management, the job of statistical processing has become convenient.

• Journal of Korean society of Dental Hygiene
• /
• v.8 no.4
• /
• pp.65-77
• /
• 2008

The purpose of this study was to offer basic data in order to make it possible for becoming the mentally more matured dental hygienist by being aware of stress factors on employment in preliminary dental hygienists and examining a coping plan according to it. The self-administered questionnaire research was carried out targeting Dental Hygiene Students at 4 colleges in metropolitan area for 1 month from October to November in 2007. Totally 209 questionnaires were collected. Among them, 206 copies were analyzed with methods in frequency analysis, correlation analysis, and ANOVA analysis by using SPSS WIN10.0 statistical program. As a result, the following conclusions were obtained. 1. 84.5% out of subjects were the active students. 95.2% and over 95.6%, respectively, were surveyed to be more than 'moderate' as for the academic achievement level and the satisfaction with college life. 2. the majority in the survey subjects were researched to receive high stress as for 'a guiding professor doesn't lead and have interest in my employment, thereby being disappointing' and 'failing to be employed is likely to lead to hurting pride so much'. 3. a coping type with stress in the survey subjects was researched to select a coping plan much as for 'sincerely hoping for the work to be well done', 'going out for a change', 'establishing a few countermeasures for solving a problem', 'overeating', and 'waiting while thinking it to be solved some time.' 4. most of stress factors had high correlation with a coping type with saying of 'trying to be alone as a whole', and had high correlation with 'failing to be employed is likely to lead to hurting pride so much' and 'overeating'. Even additionally, it was surveyed to have high correlation with 'smoking' and 'depending on the past experience'.

• Journal of Digital Contents Society
• /
• v.10 no.2
• /
• pp.357-365
• /
• 2009

To effectively exploit the underlying network bandwidth while maximizing user perceivable QoS, mandatory to make proper estimation on packet loss and queuing delay of the underling network. This issue is further emphasized in wireless network environment where network bandwidth is scarce resource. In this work, we focus our effort on developing performance model for wireless network. We collect packet trace from actually wireless network environment. We find that packet count process and bandwidth process in wireless environment exhibits long range property. We extract key performance parameters of the underlying network traffic. We develop an analytical model for buffer overflow probability and waiting time. We obtain the tail probability of the queueing system using Fractional Brown Motion (FBM). We represent average queuing delay from queue length model. Through our study based upon empirical data, it is found that our performance model well represent the physical characteristics of the IEEE 802.11b network traffic.

• Korean Journal of Construction Engineering and Management
• /
• v.24 no.2
• /
• pp.37-49
• /
• 2023

In this study, we proposed resource allocation methodologies to improve the productivity of steel bridge manufacturing plants based on the constraint theory which is very popular in the area of manufacturing industries. To this end, after defining the painting process as a bottleneck, three resource allocation methodologies were developed: Operation Specific Resource Allocation (OSRA), Product Specific Resource Allocation (PSRA), and General Resource Allocation (GRA). As a result of experiments for performance evaluation using a simulation model of the steel bridge supply chain, GRA showed the best performance in terms of the Number of Work-In-Process (NWIP) and Waiting Time (WT), in particular, as workload itself and its variability were increased, the performance gap with the specific resource allocation became further deepened. On average, GRA reduced NWIP by 36.2% and WT by 34.6% compared to OSRA, and reduced NWIP by 71.0% and WT by 70.4% compared to PSRA. The reduction of NWIP and WT means alleviating the bottleneck of the painting process, which eventually means that the productivity of the steel bridge manufacturing plant has improved.

• Quality Improvement in Health Care
• /
• v.1 no.2
• /
• pp.44-59
• /
• 1994

Medical consumers(patients) want evening-clinic because of busy work. For patient's convenience and improving service, hospital should accept it. Considering payment system and patient's demand, personnel expenses, hospital can not accept. The practice of shift system to accept patient's demand and hospital's economic aspect was made. To analysis the effect of the system and probability to alternative to evening clinic this study was done. This study was composed of basal study, intervention, evaluation of effect. The basal study were composed of studying demand on evening clinic, the number of beds, doctors employee, the time table of practice and work, and the number of patients at arrival time. The intervention composed of changing of practice time, changing of working time by the number of patients at arrival time, increasing of employee. The evaluation of effect were composed of evaluating the number of patient at time, the effect of shift system, the comparison of the number of in and out patients and questionnairing the practice of shift system. In the practice time at 2 shift system First team works 7-15 hours and Second team 12-20 hours. there are no lunch and supper time. At 18-20 hours the number of patients were 25-30. The number of patient a depart were 6-7. The number of out-patient increase in 13% and inpatient increase in 10% before the system. Doctors(100%), employee(94.6%), and patients(86.4%) approved this system. The advantage of this system were utilization of surplus time, lengthen the practice time, even distribution of patients and shortening of waiting time, rapid treatment of emergent patients. The disadvantage of this system were shortage of manpower, not all depart practice, continuity of practice, no lunch and supper time, irregular rounding. At present because of small Demanding on evening clinic, this shift system was economical. To succeed this study more effectively all depart in hospital participate. But because of economical reason it is impossible for hospital to do it. If the government assist the economic loss that all depart participate in this system it is very helpful for hospital to succeed in implementing this system more early.

• Journal of KIISE:Databases
• /
• v.35 no.3
• /
• pp.257-271
• /
• 2008

Wireless broadcast environments has character that a number of mobile client can receive data streaming from central server no matter how they are so many. Because it is asymmetric bandwidth in that uplink and downlink bandwidth are different. This advantage helps wireless broadcast environments is used in many applications. These applications work almost read operation and need control concurrency using transaction unit. Previous concurrency control scheme in single channel is not adapted in multi channel environments because consistency of data are broken when a mobile client tunes in a broadcast cycle in a channel and then move into another channel and listen to different broadcast cycle with already accessed broadcast cycle. In this paper, we propose concurrency control for read-only mobile transactions in multiple wireless broadcast channel. First of all, we adapt index and data dedicated channel and propose LBCPC(Longest Broadcast Cycle Per Channel) as new unit of consistency. In index dedicated channel, it is repeatedly broadcasted data in same BCPC(Broadcast Cycle Per Channel) until LBCPC. And mobile transaction executes validation using control information every LBCPC. As a result, consistency of data is kept and average response time is shorter than one in single channel because waiting time for restart reduces. And as control information is broadcasted more frequently than in single channel, it is guaranteed currency about data accessed by transaction. Finally, according to the simulation result, we verify performance of our scheme in multi channel as comparing average response time with single channel.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.622-628
• /
• 2019

"It's Only the End of the World" is a work that expresses in depth the perception, attitude, and reflection of a person's death. Composed of a simple story of a protagonist who has been diagnosed with AIDS and has been visiting his hometown for the first time in 12 years, this work constantly asks us what a family is in this process. The visit, which aims to inform one's condition, restore the relationship with his family as he wished, and foremost but in a beautiful parting, reveals the feelings of resentment, hatred and criticism between the family members who have been hiding or trying to accept. Are family relationships always understood and must be forgiven and cared for? The director looks into the abyss of the relationship and reveals the painful truth we wanted to hide. And we realize that this painful truth is a reality. Louis's negative stance, and the complaints and dissatisfaction of the family members who were waiting for him were absolutely inadequate in narrowing the gap. This family, each of whom has a wound and does not really understand each other, shows a deep bond of feelings toward each other, though they are tied together in a 'family' community.