• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.207-209
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• 2015

SDN은 기존 네트워크 장비의 하드웨어와 제어 부분을 분리하는 새로운 네트워크 기술로 중앙 집중 형태를 통해 효율적인 네트워크 관계가 가능하다. IoT 네트워크는 주변의 수많은 장치들을 상호 연결하는 환경으로, 각 장비의 연결과 통신, 발생하는 데이터의 빠른 처리가 요구된다. 본 논문에서는 IoT 네트워크에서 발생하는 빅데이터를 실시간으로 분석 및 처리하고, 최적화된 SDN 컨트롤러를 이용해 IoT 환경에서 효율적인 데이터 처리 및 네트워크 관제가 가능한 SDN 기반 IoT 플랫폼을 제안한다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.11a
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• pp.381-384
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• 2007

유비쿼터스 센서 네트워크 기술은 새로운 컴퓨팅 패러다임인 유비쿼터스 컴퓨팅의 핵심 분야로서, 무선 센서 네트워크를 이용한 상황정보 모니터링 시스템에 적합한 기술이다. 이 기술을 모니터링 시스템에 적용하면 열악한 환경에 간편하고 저렴한 비용으로 실시간으로 발생된 상황데이터를 수집 및 분석하여 즉각적인 상황대처와 사용자가 원하는 환경의 조건을 효율적으로 수행할 수 있다. 한편, 센서 네트워크 미들웨어는 에너지 사용에 제약을 가지는 센서 네트워크의 요구사항과 다양한 서비스 제공을 위한 서비스 확장성을 고려하여 센서 네트워크와 응용 서비스가 상호 분리되어 각각의 기능을 수행하고 제어 및 모니터링이 쉽도록 설계되어야 한다. 본 논문에서는 유비쿼터스 센서 네트워크 기반에서 무선 노드의 센싱 기술을 이용하여 영역기반 상황 정보 관리 미들웨어를 제안한다. 제안된 시스템은 수집될 데이터의 양이 적고 지속적인 모니터링이 불필요하고 일정한 간격으로 특정 지역에서 발생되는 상황을 감지하는 작업에 기존 유선 통신을 이용한 상황감시보다 효율적이다.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.56-66
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• 2016

Robustness is essential for model based FDI (Fault Detection and Isolation) and it is inevitable to have modeling errors and sensor signal noises during the process of FDI. This study suggests an improved method by applying NARX (Nonlinear Auto Regressive eXogenous) model and Kalman estimator in order to cope with problems caused by linear model errors and sensor signal noises in the process of fault diagnoses. Fault decision is made by the probability of the trend of gradually accumulated errors applying Fuzzy logic, which are robust to instantaneous sensor signal noises. Reliability of fault diagnosis is verified under various fault simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.661-669
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• 2004

As a large number of distributed systems becoming more popular, interoperability, portability and security are becoming major concerns of modern computing. CORBA and object-oriented database which provide transparency of network and database are increasingly being used as the basis for distributed system to solve these problems. The two methods can help accomplish assurance of security by using a method-based access control technique or an attribute-based access control technique. These methods also enhance the unavailability or inefficiency caused by the delay of access process and bottleneck of the network due to the complex instance-based access control. We propose a security model on the type information based access control system that can enhance both security and availability by separating the functions delivered from CORBA and object-oriented databases. We apply the access control model specifically to enhancement of security system and also perform a test to verify the security and availability of our model.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.8
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• pp.455-476
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• 2006

An avatar script language consists of commands set which is used to control avatar behaviors in cyberspace. The script language should be abstract from complex low-level concepts, so that a user can write down a scenario script easily without concerning about physical motion parameters. Also, the script should be defined in a standard format and structure to allow reusing in various implementation tools. In this paper, a layered script language is proposed for avatar behavior representation and control, which consists of task-level behavior, high-level motion and primitive motion script language. The script language of each layer represents behavior elements for a scenario scripting interface, an avatar motion sequence, and geometric information of implementation environment, respectively. Therefore, a user can create a scenario script by abstract behavior interface and a script can be applied to various implementations by the proposed translating process. A presentation domain is chosen for applying the proposed script language and the implementation result shows that the script is flexibly applied in several applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.359-366
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• 2016

The normal tissue in radiation therapy, to minimize radiation, it is most important to maximize local tumor control rates in intensive research the exact dose to the tumor sites. Therefore, the initial, therapist accuracy of detecting movement of the patient fatigue therapist has been a problem that is weighted down directly. Also, by using a web camera, a difference value between the image to be updated to the reference image is calculated, if the result exceeds the reference value, using the system for determining the motion has occurred. However, this system, it is not possible to quantitatively analyze the movement of the patient, the background is changed when moving the treatment bed in the co-therapeutic device was not able to sift the patient. In this paper, using a alpah(${\alpha}$) filter index is an attempt to solve these limitations points, quantifies the movement of the patient, by separating a background image of the patient and treatment environment, and movement of the patient during treatment It senses only, it was possible to reduce the problems due to patient movement.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.525-536
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• 2012

This paper proposes methods of securing Smart Grid system against various types of cyber threats by separating AMI networks from the public network, the Internet, and providing an AMI specific authentication framework. Due to the fact that thousands and millions of AMI devices to be deployed would be directly or indirectly connected to the public network without any authentication procedures for access control, currently being developed AMI architectures could be widely exposed to considerable number of penetrating attacks. Furthermore, there have not been a sufficient number of researches on authentication frameworks with basis on the specific circumstances of AMI networking that should support varied authentication protocols among security associations and AMI linking devices. This work makes a proposal of isolating smart meters from HAN devices and the Internet and integrating network/application level authentication frameworks with an EAP-based authentication architecture. These approaches are beneficial to deploy AMI with security and efficiency.

• Journal of the Korean Electrochemical Society
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• v.25 no.4
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• pp.134-153
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• 2022

Regardless of a trade-off relationship between energy density and safety, it is essential to improve both properties for future lithium secondary batteries. Especially, to improve the energy density of batteries further, not only thickness but also weight of separators including ceramic coating layers should be reduced continuously apart from the development of high-capacity electrode active materials. For this purpose, an attempt to replace conventional slurry coating methods with a deposition one has attracted much attention for securing comparable thermal stability while minimizing the thickness and weight of ceramic coating layer in the separator. This review introduces state-of-the-art technology on ceramic-coated separators (CCSs) manufactured by the deposition method. There are three representative processes to form a ceramic coating layer as follows: chemical vapor deposition (CVD), atomic layer deposition (ALD), and physical vapor deposition (PVD). Herein, we summarized the principle and advantages/disadvantages of each deposition method. Furthermore, each CCS was analyzed and compared in terms of its mechanical and thermal properties, air permeability, ionic conductivity, and electrochemical performance.

• Membrane Journal
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• v.31 no.6
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• pp.393-403
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• 2021

Enzymes are important class of catalyst for biotransformation. Stability and reusability of enzymes during the catalysis process is a key issue. Activity of enzyme can be enhanced by its immobilization on a suitable substrate by creation of specific microenvironment. A variety of membranes has been used as substrate due to the biocompatibility and simpler method to tune hydrophilicity/hydrophobicity property of the membrane surface. In this review, polymer membranes including cellulose, polyacrylonitrile (PAN), polydimethylsiloxane (PDMS), polyvinylidene fluoride (PVDF), polyethersulfone (PES) are introduced and discussed in detail. Biodegradation of organic contaminants by immobilized enzyme is an environmental friendly process to reduce the contamination of environment in pharmaceutical company and textile industries. The controlled hydrolysis of oil can be performed in enzyme immobilized membrane bioreactor (EMBR), resulting in reducing carbon emission and reduced environmental pollution. Bioethanol and biodiesel are considered alternative fossil fuels that can be prepared in EMBR.

• Journal of the Korean GEO-environmental Society
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• v.11 no.1
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• pp.5-11
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• 2010

The objective of this study is to evaluate the effect of operational parameters such as rotation speed and vibrating milling time for the fabrication of photocatalytic $TiO_2$ thin film using aerosol deposition methods. $TiO_2$ powders produced in the range of 1,000-3,000 rpm of rotation speed of centrifugal separator are ineffective on the fabrication of $TiO_2$ thin film by aerosol deposition due to the problem of nozzle powder jam. $TiO_2$ powders controlled by vibrating milling had about 420 nm of average diameter after 2 hr of vibrating milling time. The result of XRD analysis indicated that $TiO_2$ powders had a anatase phase. Vibrating milling methods was considered to be an effective pre-treatment process for $TiO_2$ powder control. Consequently $TiO_2$ photocatalytic thin film with dispersion of anatase crystallites controled by vibrating milling was successfully fabricated by aerosol deposition. The permeation flux of $TiO_2$ photocatalytic thin film with the immobilized $TiO_2$ powder was higher than that of suspended $TiO_2$ powder. Therefore, $TiO_2$ photocatalytic thin film promises to be one of the effective methods for enhancing filtration performance for the treatment of organic pollutants.