• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.149-157
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• 2012

In this thesis, the problem of computing approximate answers to continuous sliding-window joins over data streams when the available memory may be insufficient to keep the entire join state. One approximation scenario is to provide a maximum subset of the result, with the objective of losing as few result tuples as possible. An alternative scenario is to provide a random sample of the join result, e.g., if the output of the join is being aggregated. It is shown formally that neither approximation can be addressed effectively for a sliding-window join of arbitrary input streams. Previous work has addressed only the maximum-subset problem, and has implicitly used a frequency based model of stream arrival. There exists a sampling problem for this model. More importantly, it is shown that a broad class of applications for which an age-based model of stream arrival is more appropriate, and both approximation scenarios under this new model are addressed. Finally, for the case of multiple joins being executed with an overall memory constraint, an algorithm for memory allocation across the join that optimizes a combined measure of approximation in all scenarios considered is provided.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.166-176
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• 2021

Due to urbanization and industrialization, the importance of large-scale fire prevention, management and measures is increasing day by day. However, the fire site arrival rate in Golden Time, which is a factor that can minimize large-scale fire damage, of Pohang, a large city with a population of over 500,000, is relatively low. So additional fire fighting power deployment and infrastructure investment are required. However, as budget and manpower are limited, it is necessary to selectively deploy fire fighting power and invest in infrastructure. Therefore, this study attempted to present a fire damage rating that can compare the level of fire damage, which is an index that can help selectively provide fire fighting services in Pohang and make related decisions. For the index, the OD cost matrix was used to predict fire vulnerable areas with a high probability of increasing the fire scale in the event of a fire. Also fire damage was measured by predicting the level of fire damage in the event of a fire according to population, building density, and access of fire trucks. It is expected that the fire damage rating will be able to help in various decisions related to fire fighting service deployment and services not only in Pohang city, but also in other regions.

• Journal of KIISE:Information Networking
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• v.30 no.5
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• pp.581-594
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• 2003

Recently, a location management is being more important in mobile communication systems due to an explosive increase of mobile users. Current systems have used a concept of location area. Based on this concept, a mobile user performs a location update whenever it moves into a new location area. However, this scheme can not avoid unnecessary location updates when a mobile user moves around with high movement rate as compared to call arrival rate. That results in tremendous location management cost. To overcome this drawback, our proposal divides service areas into two sets: One is a set of areas that mobile users move with high speed and another is a set of areas that they move with low speed. After establishing these two sets, this paper employs different location tracking schemes for each sets. Generally, most mobile users with high speed have a low CMR and a regular direction until they arrive at their destination. Using such the moving behavior, systems can predict a mobile user's next location area in advance. When the mobile user moves into the predicted location, our proposal does not perform a location update. Thus, it can reduce overall location management cost. The Markov model is used to analyze the performance of our proposal. Using the model, this paper compares our proposal with IS-41 and TLA. The analytic results show that as CMR grows lower, an overall cost of our proposal becomes less, particularly if a mobile user frequently moves into the specific location are predicted by mobile systems. Also, our proposal has a better performance than other two schemes when the communication cost between HLR and VLR is high.

• The Journal of the Korea Contents Association
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• v.21 no.10
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• pp.38-47
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• 2021

This study is about a blockchain-based collective quarantine management system and its commercialization model. The configuration of this system includes a biometric information transmission unit that generates biometric information based on measured values generated from wearable devices, a biometric information transmission unit that transmits biometric information generated here from a quarantine management platform, and action information transmitted from the community server. is a system including an action information receiving unit for receiving from the quarantine management platform. In addition, a biometric information receiving unit that collects biometric information from the terminal, an encryption unit that encodes biometric information generated through the biometric information receiving unit based on blockchain encryption technology, and a database of symptoms of infectious diseases to store symptom information and an infection diagnosis database. The generated database includes a location information check unit that receives from the terminal of the user identified as a symptomatic person and determines whether the user has arrived in the community based on the location information confirmation unit and the location of the user after the location is confirmed. It includes a community arrival judgment unit that judges. And, the community server helps the interaction between the generated information. Such a blockchain based collective quarantine management system can help to advance the existing quarantine management system and realize a safer and healthier society.

• The Journal of Society for e-Business Studies
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• v.10 no.1
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• pp.61-80
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• 2005

Business Process Management (BPM) System is a software system to support an efficient execution, control and management of business processes. The system automates complex business processes and manages them effectively to raise productivity. Traditional commercial systems mainly focus on automating processes and do not have methods for enhancing process performances and task performer's efficiency. Therefore, there is room for enhancement of task performers' productivities and efficiency of business processes. In this paper, we propose a new method of executing business processes more efficiently in that a whole process is scheduled considering the degree of participants' workload. The method allows managing the largest constraints among constituent resources of the process. This method is based on the DBR (Drum-Buffer-Rope) in TOC (Theory of Constraints) concepts. We first consider the differences between business process models and DBR application models, and then develop the modified drum, buffer and rope. This leads us to develop BP-DBR (Business Process-DBR) that can control the proper size of task performers' work list and arrival rate of process instances. Use of BP-DBR improves the efficiency of the whole process as well as participants' working condition. We then carry out a set of simulation experiments and compare the effectiveness of our approach with that of the scheduling techniques used in existing systems.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.2
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• pp.133-148
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• 2011

Construction sites are becoming larger and complex with the growth of national economy. Accordingly, it is important to identify real-time information about materials, equipments, and manpower during construction at sites. Even though research utilizing position tracking sensors has been conducted in architectural engineering fields, this area of research is almost nil in civil engineering fields. Therefore, a feasibility study to find a way to apply position tracking sensors to an in-situ tunnel construction site adopting conventional tunnelling method is performed in this study. A methodology is proposed that the progress management of the tunnelling work can be monitored by checking construction materials needed at job site and the safety management system can be assessed by checking distance between in-situ workers and construction equipments. The most representative materials were identified so that IT technology can be applied by attaching and monitoring sensors to the selected materials. Also, time of arrival (TOA) for a position determination technology along with a wireless network technology was chosen and build wireless network system. The adopted methodology was applied to an in-situ tunnelling site, and verified the usefulness of the proposed system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.5
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• pp.23-36
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• 2010

Signcryption is a cryptographic primitive which offers authentication and confidentiality simultaneously with a cost lower than signing and encrypting the message independently. We propose a new cryptographic notion called Identity-based online/offline signcryption. The notion of online/offline scheme can be divided into two phases, the first phase is performed offline prior to the arrival of a message to be signed or encrypted and the second phase is performed online phase after knowing the message and the public key of recipient. The Online phase does not require any heavy computations such as pairings or exponents. It is particularly suitable for power-constrained devices such as smart cards. In this paper, we propose ID-based signcryption scheme and ID-based online/offline signcryption scheme where the confidentiality and authenticity are simultaneously required to enable a secure and trustable communication environment. To our best knowledge, this is the first ID-based online/offline signcryption scheme that can be proven secure in the standard model.

• The Korean Journal of Pain
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• v.33 no.4
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• pp.386-394
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• 2020

Background: In the emergency department (ED), adequate pain control is essential for managing patients; however, children with pain are known to receive less analgesia than adults with pain. We introduce the Pain Passport to improve pain management in paediatric patients with suspected fractures in the ED. Methods: This was a before-and-after study. We reviewed the medical records of paediatric patients who were primarily diagnosed with fractures from May to August 2015. After the introduction of the Pain Passport, eligible children were enrolled from May to August 2016. Demographics, analgesic administration rates, time intervals between ED arrival and analgesic administration, and satisfaction scores were obtained. We compared the analgesic prescription rate between the two periods using multiple logistic regression. Results: A total of 58 patients were analysed. The baseline characteristics of subjects during the two periods were not significantly different. Before the introduction of the Pain Passport, 9 children (31.0%) were given analgesics, while after the introduction of the Pain Passport, a significantly higher percentage of patients (24/29, 82.8%) were treated with analgesics (P < 0.001). The median administration times were 112 (interquartile range [IQR], 64-150) minutes in the pre-intervention period and 24 (IQR, 20-74) minutes in the post-intervention period. The median satisfaction score for the post-intervention period was 4 (IQR, 3-5). The adjusted odds ratio for providing analgesics in the post-intervention period was 25.91 (95% confidence interval, 4.36-154.02). Conclusions: Patient-centred pain scoring with the Pain Passport improved pain management in patients with suspected fractures in the paediatric ED.

• Journal of the Korean Dietetic Association
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• v.9 no.3
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• pp.219-232
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• 2003

The purposes of this study were to assess the child care centers' foodservice facility, and to develop the kitchen facility model based on the general sanitation standards and guidelines in order to provide basic information for a plan review to build or renovate child care centers' foodservice facility. The scopes of the study include : 1) field assessment of the foodservice management practices and facilities in 8 public child care centers, and 2 private child care centers which they are subsidized from the government as public child care centers, 2) development of child care centers' kitchen facility model based on the General Sanitation Standards and Guidelines. The results of this study can be summarized as follows : 1. Field Assessment of the Child Care Centers' Foodservice Facility Average number of children in child care centers was 78.0$\pm$24.20, the average space of kitchen was 15.13$\pm$4.25($m^2$). Especially, the average space of kitchen was 18.49$\pm$4.35($m^2$) with enrollment capacity of 90～120 children in child care centers. The inventory level of most foods was relatively low except rice and kimchi. Kitchen facilities and equipments were similar to those of home kitchen and did not meet the standards of institutional practice. Therefore, the director in child care centers should recognize the importance of the sanitation management and pay more attention to the renovation of foodservice facilities as well as sanitation management practices. 2. Development of the Kitchen Facility Model based on the General Sanitation Standards and Guidelines The kitchen facility plan model with enrollment capacity of 100 children was developed based on the results of field assessment and literature review. Suggested kitchen space was 34.16$m^2$(6,100mm×5,600mm). This space was bigger than the results of field survey or precedent study, considered appropriate to implement the general sanitation standards. The main feature of the developed kitchen facility plan and model was product flow in one direction from the arrival of the raw material to the finished product in order to prevent cross contamination and to improve working efficiency.

• Journal of Trauma and Injury
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• v.29 no.4
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• pp.155-160
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• 2016

Purpose: Two years have passed since a level I trauma center was officially opened in the Gacheon Gil Hospital, South Korea. We analyzed 2014 and 2015 registered patient data from the Korean Trauma Data Base (KTDB) to identify trends in trauma patient care and factors that influence the quality of trauma care at the Gacheon Gil trauma center. Methods: Data was extracted from the KTDB included patient age, sex, systolic blood pressure at emergency room arrival, revised trauma score, injury severity score, trauma injury severity score, transfusion amount, and the cause of death was analyzed. Results: A total of 3269 trauma patients were admitted to our trauma center in 2014 and 3225 in 2015. Demographics and mechanism of injury were not significantly different between years. The severity of trauma injury was decreased in 2015 although the mortality rate was slightly increased. This requires further analysis. Conclusion: The aim of this study was to determine the general status and trends in trauma incidence and management outcomes for the Incheon area. We noted no significant changes in trauma status from 2014 to 2015. We need to collect and review trauma patient data over a long period in order to elucidate trauma incidence and management trends in the trauma field. Finally, studies using trauma patient data will indicate appropriate quality control factors for trauma care and help to improve the quality of trauma management.