• Journal of Korean Academy of Nursing
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• v.45 no.2
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• pp.280-292
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• 2015

Purpose: In this study a system dynamics methodology was used to identify correlation and nonlinear feedback structure among factors affecting unplanned extubation (UE) of ICU patients and to construct and verify a simulation model. Methods: Factors affecting UE were identified through a theoretical background established by reviewing literature and preceding studies and referencing various statistical data. Related variables were decided through verification of content validity by an expert group. A causal loop diagram (CLD) was made based on the variables. Stock & Flow modeling using Vensim PLE Plus Version 6.0b was performed to establish a model for UE. Results: Based on the literature review and expert verification, 18 variables associated with UE were identified and CLD was prepared. From the prepared CLD, a model was developed by converting to the Stock & Flow Diagram. Results of the simulation showed that patient stress, patient in an agitated state, restraint application, patient movability, and individual intensive nursing were variables giving the greatest effect to UE probability. To verify agreement of the UE model with real situations, simulation with 5 cases was performed. Equation check and sensitivity analysis on TIME STEP were executed to validate model integrity. Conclusion: Results show that identification of a proper model enables prediction of UE probability. This prediction allows for adjustment of related factors, and provides basic data do develop nursing interventions to decrease UE.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.393-404
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• 2007

A concept of multi-layered database is proposed for the integrated operation of bridge information in this study. The multi-layered database is a logically integrated database composed of standardized information layers. The standardized information layers represent the data sets that can be unified, and they are defined by standardized information models. Classification system of bridge component was used as a basis of the multi-layered database, and code system based on the classification system was employed as a key integrator to manipulate the distributed data located on the different information layers. In addition, data level indicating priorities of information layers was defined to support strategic planning of the multi-layered database construction. As a proof of concept, a prototype of multi-layered database for object-oriented 3-D shape information and structural calculation document was built. Data consistency check of the semantically same data in the two different information layer was demonstrated, It is expected that the proposed concept can assure the integrity and consistency of information in the bridge information management.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.161-164
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• 2005

As the power of influence of the Internet grows steadily, attacks against the Internet can cause enormous monetary damages nowadays. A worm can not only replicate itself like a virus but also propagate itself across the Internet. So it infects vulnerable hosts in the Internet and then downgrades the overall performance of the Internet or makes the Internet not to work. To response this, worm detection and prevention technologies are developed. The worm detection technologies are classified into two categories, host based detection and network based detection. Host based detection methods are a method which checks the files that worms make, a method which checks the integrity of the file systems and so on. Network based detection methods are a misuse detection method which compares traffic payloads with worm signatures and anomaly detection methods which check inbound/outbound scan rates, ICMP host/port unreachable message rates, and TCP RST packet rates. However, single detection methods like the aforementioned can't response worms' attacks effectively because worms attack the Internet in the distributed fashion. In this paper, we propose a design of distributed worm detection system to overcome the inefficiency. Existing distributed network intrusion detection systems cooperate with each other only with their own information. Unlike this, in our proposed system, a worm detection system on a network in which worms select targets and a worm detection system on a network in which worms propagate themselves cooperate with each other with the direction-aware information in terms of worm's lifecycle. The direction-aware information includes the moving direction of worms and the service port attacked by worms. In this way, we can not only reduce false positive rate of the system but also prevent worms from propagating themselves across the Internet through dispersing the confirmed worm signature.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.291-295
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• 2007

FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL consists of In-Pile Test Section (IPS) and Out-Pile System (OPS). FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. Task Force Team was organized to do a construction systematically and the communication between members of the task force team was done through the CoP(community of Practice) notice board provided by the Institute. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. Without a sweet of the workers of the participating company of HEC(Hyundae Engineering Co, Ltd), HDEC(HyunDai Engineering & Construction Co. Ltd), equipment manufacturer, and the task force team, it is not possible to install the FTL facility within the planned shutdown period. The Commissioning of the FTL is on due to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.492-505
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• 2007

Currently, most procedures in domestic facility management systems are performed by hand. However, these manually operated facility management systems involve critical limitations, such as a waste of manpower to store collected data into a database, intentional or accidental loss of data consistency (mainly due to a lack of the ability to recognize and deal with frequent changes of facility status in realtime), and so on. To overcome the limitations of such manually operated facility management systems, the following capabilities must be supported. First, the changes in facility status must be recognized in realtime. Second, the data collection process must be secure and reliable to prevent fabrication of collected data and preserve data integrity. Third, the data collection devices must be portable to help the manager collect data about their facilities. To address these problems, we design and implement a novel facility management system using portable RFID, which is designed to support these functionalities and thus help reduce administrative costs. Through extensive experiments, we observed that our system improved the accuracy and reliability of facility check process and helped cut administrative costs by significantly reducing failure frequency.

• Journal of KIISE:Databases
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• v.34 no.6
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• pp.493-502
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• 2007

Due to a growing interest in searching and expressing knowledge effectively, knowledge management methods such as Topic Map are becoming more important. Topic Map organizes knowledge that is full of intricate relations, so maintaining and managing Topic Map consistently is very essential. TMCL and other constraint languages have limits as they can check simple constraints but can not support complex constraints like dependence constraints. Current constraint checking systems operating at the application level are also showing an inferiority in performance. In this paper, we extend TMCL based on the characteristics of other constraint languages in the information system field and related fields. We build and propose an RDBMS-based Topic Map constraint checking system to support the extended constraint language effectively. This new system handles complex types of constraints like dependency constraint as well as basic Topic Map constraints present in the TMCL. As the system examines each constraint it uses templates to generate queries for effective checking and overall shows a higher performance level than current systems.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.6
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• pp.589-593
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• 2008

These days, as a side effect of the growth of the mobile devices, malwares for the mobile devices also tend to increase and become more dangerous. Because embedded Linux is one of the advanced OSes on mobile devices, a solution to preventing malwares from infecting and destroying embedded Linux will be needed. We present a scheme using signature verification for embedded Linux that prevents executallle-Infecting malwares. The proposed scheme works under collaboration between mobile devices and a server. Malware detection is delegated to the server. In a mobile device, only integrity of all executables and dynamic libraries is checked at kernel level every time by kernel modules using LSM hooks just prior to loading of executables and dynamic libraries. All procedures in the mobile devices are performed only at kernel level. In experiments with a mobile embedded device, we confirmed that the scheme is able to prevent all executable-Infecting malwares while minimizing damage caused by execution of malwares or infected files, power consumption and performance overheads caused by malware check routines.

• The Journal of Society for e-Business Studies
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• v.17 no.4
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• pp.1-16
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• 2012

Shieh and Wang [10] recently proposed an efficient mutual authentication scheme that combined the cost-effectiveness of operations of Lee et al. [6]. scheme and the security and key agreement of Chen and Yeh scheme. Shieh and Wang [10] scheme, however, does not satisfy the security requirements against a third party (the man-in the middle, attacker) that have to be considered in remote user authentication scheme using password-based smart cards. Shieh and Wang weaknesses are the inappropriateness that it cannot verify the forged message in 3-way handshaking mutual authentication, and the vulnerability that the system (server) secret key can easily be exposed. This paper investigates the problems of Shieh and Wang scheme in the verification procedure of the forged messages intercepted by the eavesdrop. An enhanced two-way remote user authentication scheme is proposed that is safe and strong against multiple attacks by adding the ability to perform integrity check on the server and proposed scheme is not expose user password information and the system's confidential information.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.1-7
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• 2018

As IT technology develops recently, medical equipment used in hospitals is demanding high performance. However, since the user visits different hospitals depending on the user's situation, the medical information treated at the hospital is distributed among the hospitals. In this paper, we propose a model to efficiently integrate the health care information of the users stored in the hospital in order to collect the healthcare information of the users who visited the different hospitals. The proposed model synchronizes users' healthcare information collected from personal wearable devices to collect user - centered healthcare information. In addition, the proposed model performs integrity and validity check related to user's healthcare information in a database existing in a cloud environment in order to smoothly share data with the healthcare service center. In particular, the proposed model enables tree - based data processing to smoothly manage healthcare information collected from mobile platforms.

• The Journal of the Acoustical Society of Korea
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• v.15 no.5
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• pp.21-29
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• 1996

Industrial equipment, such as power plant, is required to operate reliably, continuously and economically under rather severe conditions of temperature, stress, and enbironment. To test structural integrity and fitness, ultrasonic nondestructive testing is used because of effectiveness and simplicity. In this paper, wavelet transform based least mean square(LMS) algorithm is applied to reduce the influence of the interference occurring between randomly positioned small scatters. The RUN test is performed to check the nonstationarity of the speckle noise signal. The performance of this new approach is compared with that of the time domain LMS algorithm by means of condition numbers, signal-to-noise ratio and 3-D image. As a result, the wavelet transform based LMS algorithm shows better performance than the time domain LMS algorithm in this experiment.