• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.225-229
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• 2017

Micron-sized dextran particles, which now attract wide attention as a promising drug delivery systems, can be prepared via the supercritical anti-solvent (SAS) process. In SAS process, dextran particles are obtained as a result of recrystallization of dissolved dextran in dimethyl sulfoxide (DMSO) on addition of supercritical $CO_2$ as an anti-solvent. In this work, with an intention to provide information on the feasible operating conditions of the process, the phase behavior of Dexran/DMSO/$CO_2$ is observed by measuring the cloud point in favor of a variable volume cell. From the experimental study, it is concluded that a feasible operating condition of the SAS process for preparation of dextran particles would be 300.15 K~330.15 K and 90 bar~130 bar, respectively, and solute concentration ranges from 5mg/ml to 20 mg/ml.

• The KIPS Transactions:PartB
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• v.15B no.6
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• pp.553-560
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• 2008

The amount of image data used in medical institution is increasing rapidly with great development of medical technology. Therefore, an automation method that use image processing description, rather than manual macrography of doctors, is required for the analysis large medical data. Specially, medical image registration, which is the process of finding the spatial transform that maps points from one image to the corresponding points in another image, and 3D analysis and visualization skills for a series of 2D images are essential technologies. However, a high establishment cost raise a budget problem, and hence small scaled hospitals hesitate importing these medical visualizing system. In this paper, we propose a visualization system which allows user to manage datasets and manipulates medical images registration using an open source graphics tool - VTK(Visualization Tool Kit). The propose of our research is to get more accurate 3D diagnosis system in less expensive price, compared to existing systems.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.3
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• pp.113-120
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• 2017

In recent years, indoor localization has been researched for the improvement of its localization accuracy capability in Wi-Fi environment. The fingerprint and RF propagation models has been the main approach in determining indoor positioning. With the use of fingerprint, a low-cost, versatile localization system can be achieved without the use of external hardware. However, only a few research have been made on virtual access points (VAPs) among indoor localization models. In this paper, the idea of indoor localization system using fingerprint with the addition of VAP in Wi-Fi environment is discussed. The idea is to virtually add APs in the existing indoor Wi-Fi system, this would mean additional virtually APs in the network. The experiments of the proposed algorithm shows the positive results when 2VAPs are used compared with only APs. A combination of 3APs and 2VAPs in the 3rd case had the lowest average error of 3.99 among its 4 scenarios.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.3
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• pp.135-142
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• 2017

DDoS (Distributed Denial of Service) exhausts the target server's resources using the large number of zombie pc, As a result normal users don't access to server. DDoS Attacks steadly increase by many attacker, and almost target of the attack is critical system such as IT Service Provider, Government Agency, Financial Institution. In this paper, We will introduce the CNN (Convolutional Neural Network) of deep learning based real-time detection system for DNS amplification Attack (DNS DDoS Attack). We use the dataset which is mixed with collected data in the real environment in order to overcome existing research limits that use only the data collected in the experiment environment. Also, we build a deep learning model based on Convolutional Neural Network (CNN) that is used in pattern recognition.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.87-92
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• 2007

Recently, developments of process monitoring system in order to detect and diagnose process abnormalities has got the spotlight in process systems engineering. Normal data obtained from processes provide available information of process characteristics to be used for modeling, monitoring, and control. Since modern chemical and environmental processes have high dimensionality, strong correlation, severe dynamics and nonlinearity, it is not easy to analyze a process through model-based approach. To overcome limitations of model-based approach, lots of system engineers and academic researchers have focused on statistical approach combined with multivariable analysis such as principal component analysis (PCA), partial least squares (PLS), and so on. Several multivariate analysis methods have been modified to apply it to a chemical process with specific characteristics such as dynamics, nonlinearity, and so on.This paper discusses about missing value estimation and sensor fault identification based on process variable reconstruction using dynamic PCA and canonical variate analysis.

• Smart Structures and Systems
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• v.15 no.3
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• pp.683-698
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• 2015

Railroad bridges form an integral part of railway infrastructure throughout the world. To accommodate increased axel loads, train speeds, and greater volumes of freight traffic, in the presence of changing structural conditions, the load carrying capacity and serviceability of existing bridges must be assessed. One way is through system identification of in-service railroad bridges. To dates, numerous researchers have reported system identification studies with a large portion of their applications being highway bridges. Moreover, most of those models are calibrated at global level, while only a few studies applications have used globally and locally calibrated model. To reach the global and local calibration, both ambient vibration tests and controlled tests need to be performed. Thus, an approach for system identification of a railroad bridge that can be used to assess the bridge in global and local sense is needed. This study presents system identification of a railroad bridge using free vibration data. Wireless smart sensors are employed and provided a portable way to collect data that is then used to determine bridge frequencies and mode shapes. Subsequently, a calibrated finite element model of the bridge provides global and local information of the bridge. The ability of the model to simulate local responses is validated by comparing predicted and measured strain in one of the diagonal members of the truss. This research demonstrates the potential of using measured field data to perform model calibration in a simple and practical manner that will lead to better understanding the state of railroad bridges.

• Journal of Korean Society of Archives and Records Management
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• v.18 no.3
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• pp.49-70
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• 2018

This paper proposes a cloud system model for incorporating the existing Records Management System (RMS), Archives Management System (AMS), and Central Archives Management System (CAMS) into a cloud-based national records management system. To do this, research on concrete and stepwise ways to transform AMS, including CAMS, into a cloud computing environment was carried out. This study developed a cloud system design strategy and goal model to integrate national records-related systems into a single cloud system to share and utilize information resources, manage them efficiently, and reduce costs. In particular, this study analyzed technical security and operational security that are exposed in the cloud environment and suggested measures to solve them. As a result, cloud computing technology can be applied to achieve low-cost and high-efficiency effects.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.33-41
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• 2011

Due to the recent quantum leaps forward in bio-, nano-, and information-technologies (BT, NT and IT), the precisionization and miniaturization of mechanical and electrical components are in high demand. In particular, the ITrelated equipments that take a great part in our domestic industry are in the area requiring high precision technologies. As a consequence, the researches on the development vibration isolation systems that diminish external disturbance or internal vibration are highly required. Among the components comprising the vibration isolation system, air spring has become on a focal point for the researchers due to its merits. This air spring is able to support heavy loads, keep a low natural frequency despite of having a lower value of stiffness, and control the performance of vibration isolation. However, sometimes the sole use of air spring is in demand due to some economic reasons. Under this circumstance, the damping effect of sole air spring may not enough to reduce sufficient amount of vibration. In this study, the air spring mount system connecting with an external chamber is proposed to increase or control the damping effect. To investigate its damping mechanism, the thermal and dynamic behaviors of the system is examined through a theoretical modeling approach in this part of research. In this approach, thermomechanical and Helmholtz resonator type models are to be employed for the air spring/external chambers and connecting tube system, respectively. The frequency response functions (FRFs) derived from the modeling effort are evaluated with physical parametric values and the effects of connecting tube length on these FRFs are identified through computer simulations.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.191-203
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• 2015

IT is based industry on finance and insurance services and is essential equipment of survival for competitive on market. The importance of IT industry on finance and insurance is bigger than other industries. So, This study examinate effects of hardware and software divided by IT industry on each 6 finance and insurances. Research models are production inducing effects of Demand-Driven model, Shortage effects of Supply-Driven model finally, Leontief's price model by using data for analysis is Input-Output table for 2000~2009. Results are that IT Service effects are more impact than IT hardware effects on Finance and Insurance Service. Especially, IT service's supply shortage effects is 0.0847KWR to produce 1KRW of finance and insurance service for 2-fold increase compared to 2000. In addition, Central Bank and banking institutions of finance and insurance services are the greatest impact from IT industry. These are which is increasing to interdependence between IT industry and finance and insurance service.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.199-211
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• 2018

Ever since Korea was geopolitically divided into North and South Korea in the 1940s, South Korea has depended on maritime transportation for global trade and logistics. Now, however, South Korea is preparing to develop a new global route for trans-Eurasia logistics passing through North Korea. Even though there are difficulties to overcome, South Korea expects that a new overland route, shorter than the existing seaways in the Europe-Asia section, will bring more frequent trade with more rapid and cost-effective logistics services in the future. Related to this issue, this study aims to proactively analyze dynamic logistics changes in South Korea when a trans-Korea railway is developed and linked with the trans-China railway and the trans-Siberian railway. This study employed a system dynamics simulation approach to model the logistics system in South Korea. The simulation results indicated that the traffic of the Uiwang inland container depot near the capital area may increase but the traffic of the Port of Busan may decrease. With supplementary research, consequently, follow-up studies on adjusting the traffic capacity in Korea are required to attain successful trans-Eurasia logistics by rail.