• Clinical and Experimental Pediatrics
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• v.57 no.4
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• pp.178-185
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• 2014

Purpose: Blood culture is the most important tool for detecting bacteremia in children with fever. However, blood culture contamination rates range from 0.6% to 6.0% in adults; rates for young children have been considered higher than these, although data are limited, especially in Korea. This study determined the contamination rate and risk factors in pediatric patients visiting the emergency room (ER) or being admitted to the ward. Methods: We conducted a retrospective chart review of blood cultures obtained from children who visited Yonsei Severance Hospital, Korea between 2006 and 2010. Positive blood cultures were labeled as true bacteremia or contamination according to Centers for Disease Control and Prevention/National Healthcare Safety Network definitions for laboratory-confirmed bloodstream infection, after exclusion of cultures drawn from preexisting central lines only. Results: Among 40,542 blood cultures, 610 were positive, of which 479 were contaminations and 131 were true bacteremia (overall contamination rate, 1.18%). The contamination rate in the ER was significantly higher than in the ward (1.32% vs. 0.66%, P<0.001). The rate was higher in younger children (2.07%, 0.94%, and 0.61% in children aged <1 year, 1-6 years, and >6 years, respectively). Conclusion: Overall, contamination rates were higher in younger children than in older children, given the difficulty of performing blood sampling in younger children. The contamination rates from the ER were higher than those from the ward, not accounted for only by overcrowding and lack of experience among personnel collecting samples. Further study to investigate other factors affecting contamination should be required.

• Journal of Astronomy and Space Sciences
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• v.34 no.4
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• pp.303-314
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• 2017

With increased human activity in space, the risk of re-entry and collision between space objects is constantly increasing. Hence, the need for space situational awareness (SSA) programs has been acknowledged by many experienced space agencies. Optical and radar sensors, which enable the surveillance and tracking of space objects, are the most important technical components of SSA systems. In particular, combinations of radar systems and optical sensor networks play an outstanding role in SSA programs. At present, Korea operates the optical wide field patrol network (OWL-Net), the only optical system for tracking space objects. However, due to their dependence on weather conditions and observation time, it is not reasonable to use optical systems alone for SSA initiatives, as they have limited operational availability. Therefore, the strategies for developing radar systems should be considered for an efficient SSA system using currently available technology. The purpose of this paper is to analyze the performance of a radar system in detecting and tracking space objects. With the radar system investigated, the minimum sensitivity is defined as detection of a $1-m^2$ radar cross section (RCS) at an altitude of 2,000 km, with operating frequencies in the L, S, C, X or Ku-band. The results of power budget analysis showed that the maximum detection range of 2,000 km, which includes the low earth orbit (LEO) environment, can be achieved with a transmission power of 900 kW, transmit and receive antenna gains of 40 dB and 43 dB, respectively, a pulse width of 2 ms, and a signal processing gain of 13.3 dB, at a frequency of 1.3 GHz. We defined the key parameters of the radar following a performance analysis of the system. This research can thus provide guidelines for the conceptual design of radar systems for national SSA initiatives.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.21-30
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• 2006

As the amount of information to be processed by computers has recently been increased, there has been cluster computing systems developed by connecting PCs and workstations using high-speed networks. hs a result, the studies on a cluster-based DBMS have been done with a wide range and it is necessary to develop a cluster manager for monitoring and managing cluster-based DBMSs. But, a cluster manager for efficiently managing cluster-based DBMSs has been studied in a first step. In this paper, we design and implement a high-availability cluster manager for a cluster-based DBMS. It monitors the status of nodes in cluster systems as well as the status of DBMS instances in a node, by using a graphic user interface (GUI). Our cluster manager supports the high-availability for a cluster-based DBMS by perceiving errors and recovering them, based on the monitored information on the status of a server.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.852-857
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• 2010

As the wind has become one of the fastest growing renewable energy sources, the key issue of wind energy conversion systems is on how to efficiently operate the wind turbines in a wide range of wind speeds. In general, the wind speed is the main factor that impact on the dynamics of wind turbine system. Wind turbine algorithms are thus required to improve the performance of wind speed measurements. However, the accurate measurement of the effective wind speed using wind gauge and similar sensors is difficult such that control systems are needed for wind speed estimation using various techniques. Therefore, this research suggests the Maximum Power Point Tracking (MPPT) method for tracking the wind speed based on neural networks. Design experiments were carried out in laboratory environment to validate the application of the proposed method.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.1-11
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• 2010

The purpose of this study is, by recognizing that recently, as crimes using information and various adverse-effect phenomena such as hacking and virus occur frequently with rapid development of information network such as Internet in every field of industry, the range of security is widening to the field of industrial areas for preventing the leaking of industrial technology and protecting that technology as well as information security only limited to IT area, and by establishing common concept about industrial security through education on the industrial security at the point of increasing importance of industrial security, to prepare the base of comprehensive risk management system for protecting company's assets (physical factor, technical factor and managerial factor) safely from the random threats or attacks inside and outside the company through assessment of important assets of the company, evaluation of threats and weak points, and risk assessment by building industrial security management system in order to protect company's information assets and resources which are connected to the existence of the company safely from the threats or attacks from inside or outside the company and to spread stable business activities.

• Journal of Adhesion and Interface
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• v.9 no.3
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• pp.27-33
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• 2008

A series of aluminum acetylacetonate (AlACA) belonging in inorganic chelate calculating with the ratio of -COOH mole in PSA (0, 0.25, 0.5, 0.75, 1) and a series of PSA with different acrylic acid contents (3 wt%, 7 wt%, 10 wt%) were blended and measured gel contents, probe tack, peel strength, SAFT. With the increasing of aluminum acetylacetonate contents, the network structure was formed and gel contents were increased. Probe tack fibrillation and peel strength were decreased following the addition of aluminum acetylacetonate. SAFT were significantly changed with the change of acrylic acid contents in PSA. From these results, aluminum acetylacetonate could be used in the range of which would not change the performance a lot, and cure the PSA.

• IMMUNE NETWORK
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• v.11 no.1
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• pp.11-41
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• 2011

The discovery of microRNA (miRNA) is one of the major scientific breakthroughs in recent years and has revolutionized current cell biology and medical science. miRNAs are small (19~25nt) noncoding RNA molecules that post-transcriptionally regulate gene expression by targeting the 3' untranslated region (3'UTR) of specific messenger RNAs (mRNAs) for degradation of translation repression. Genetic ablation of the miRNA machinery, as well as loss or degradation of certain individual miRNAs, severely compromises immune development and response, and can lead to immune disorders. Several sophisticated regulatory mechanisms are used to maintain immune homeostasis. Regulatory T (Treg) cells are essential for maintaining peripheral tolerance, preventing autoimmune diseases and limiting chronic inflammatory diseases. Recent publications have provided compelling evidence that miRNAs are highly expressed in Treg cells, that the expression of Foxp3 is controlled by miRNAs and that a range of miRNAs are involved in the regulation of immunity. A large number of studies have reported links between alterations of miRNA homeostasis and pathological conditions such as cancer, cardiovascular disease and diabetes, as well as psychiatric and neurological diseases. Although it is still unclear how miRNA controls Treg cell development and function, recent studies certainly indicate that this topic will be the subject of further research. The specific circulating miRNA species may also be useful for the diagnosis, classification, prognosis of diseases and prediction of the therapeutic response. An explosive literature has focussed on the role of miRNA. In this review, I briefly summarize the current studies about the role of miRNAs in Treg cells and in the regulation of the innate and adaptive immune response. I also review the explosive current studies about clinical application of miRNA.

• Proceedings of the Korea Association of Information Systems Conference
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• 2000.11a
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• pp.1.2-24
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• 2000

The field of neural networks has been a recent surge in activity as a result of progress in developments of efficient training algorithms. For this reason, and coupled with the widespread availability of powerful personal computer hardware for running simulations of networks, there is increasing focus on the potential benefits this field can offer. The neural network may be viewed as an advanced pattern recognition technique and can be applied in many areas such as financial time series forecasting, medical diagnostic expert system and etc.. The intention of this study is to build and implement one simple artificial neural networks hereinafter called ANN. For this purpose, some literature survey was undertaken to understand the structures and algorithms of ANN theoretically. Based on the review of theories about ANN, the system adopted 3-layer back propagation algorithms as its learning algorithm to simulate one case of medical diagnostic model. The adopted ANN algorithm was performed in PC by using turbo PASCAL and many input parameters such as the numbers of layers, the numbers of nodes, the number of cycles for learning, learning rate and momentum term. The system output more or less successful results which nearly agree with goals we assumed. However, the system has some limitations such as the simplicity of the programming structure and the range of parameters it can dealing with. But, this study is useful for understanding general algorithms and applications of ANN system and can be expanded for further refinement for more complex ANN algorithms.

• Korean Journal of Computational Design and Engineering
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• v.10 no.6
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• pp.444-454
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• 2005

Recently, the requirements of multi-resolution models of a solid model, which represent an object at multiple levels of feature detail, are increasing for engineering tasks such as analysis, network-based collaborative design, and virtual prototyping and manufacturing. The research on this area has focused on several topics: topological frameworks for representing multi-resolution solid models, criteria for the level of detail (LOD), and generation of valid models after rearrangement of features. As a solution to the feature rearrangement problem, the new concept of the effective zone of a feature is introduced in the former part of the paper. In this paper, we propose a feature-based non-manifold modeling system to provide multi-resolution models of a feature-based solid or non-manifold model on the basis of the effective feature zones. To facilitate the implementation, we introduce the class of the multi-resolution feature whose attributes contain all necessary information to build a multi-resolution solid model and extract LOD models from it. In addition, two methods are introduced to accelerate the extraction of LOD models from the multi-resolution modeling database: the one is using an NMT model, known as a merged set, to represent multi-resolution models, and the other is storing differences between adjacent LOD models to accelerate the transition to the other LOD. We also suggest the volume of the feature, regardless of feature type, as a criterion for the LOD. This criterion can be used in a wide range of applications, since there is no distinction between additive and subtractive features unlike the previous method.

• Journal of the Korea Convergence Society
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• v.5 no.3
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• pp.23-27
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• 2014

In recent times, there is an increasing interest in wireless charge of smartphones and devices, and many companies are developing wireless charges. The range of application of wireless charge would be expanded to almost all electronics, including not only mobile devices, but also notebook computers and vacuum cleaners. On-line electric vehicles are to be launched in the market this year in a massive scale. As such wireless charge-related markets are inexhaustible. Wireless charge is included in the world's top 10 promising technologies, and its rapid growth is expected to have annual growth by more than 100%. However, there's a need to establish a safe environment, by analyzing security threats to technical limitations and harmfulness to human body, and arrange institutional compliments. The development of communication method for a variety of wireless charging are delivering comfortable and safe information. This paper aims to examine the factors to threaten electric vehicle, which are usually intruded through network system and analyzes security threats to and security requirements for magnetic resonance mode-based wireless charge in mobile devices, and suggests security requirements.