• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.43-49
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• 2019

The wired and wireless Internet is a useful window to easily acquire various types of media data. On the other hand, the public can easily get the media data including the object to which the personal information is exposed, which is a social problem. In this paper, we propose a method to robustly detect a target object that has exposed personal information using a learning algorithm and effectively block the detected target object area. In the proposed method, only the target object containing the personal information is detected using a neural network-based learning algorithm. Then, a grid-like mosaic is created and overlapped on the target object area detected in the previous step, thereby effectively blocking the object area containing the personal information. Experimental results show that the proposed algorithm robustly detects the object area in which personal information is exposed and effectively blocks the detected area through mosaic processing. The object blocking method presented in this paper is expected to be useful in many applications related to computer vision.

• Korean Management Science Review
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• v.11 no.1
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• pp.187-196
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• 1994

Time-Space-Time(T-S-T) switching network is modeled as a graceful degrading system. Call blocking probability is defined as a measure of performance. Several performance related measures are suggested under the presence of failure. An optimization model is proposed, which determines optimal values of system parameters of the switching network.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.119-122
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• 2006

VoD(Video on Demand) 시스템은 일반적으로 VoD 서버 및 파일 저장장소 등의 제한된 자원 하에서 운용된다. 따라서 VoD 시스템의 QoS(Quality of Service)는 VoD 서버 및 파일 저장장소가 제한된 운용 자원 하에서 클라이언트들에게 안정된 스트림 서비스를 제공함으로써 보장할 수 있다. 즉, VoD 시스템의 QoS를 보장하기 위해서는 클라이언트들의 스트림 서비스 요청이 제한된 운용자원 때문에 VoD 서버로부터 수신이 거부되거나 또는 파일 저장장소로부터 필요한 데이터 서비스를 받는 도중에 연결이 끊어져 손실되는 장애확률(blocking probability)을 최소화해야 한다. 본 연구에서는 VoD 시스템의 QoS 보장에 활용하기 위하여 VoD 시스템의 장애확률을 추정하는 모델을 개발한다.

• Wind and Structures
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• v.9 no.2
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• pp.147-158
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• 2006

The purpose of this paper is to find a more accurate method to evaluate pedestrian wind by computational fluid dynamics approach. Previous computational fluid dynamics studies of wind environmental problems were mostly performed by simplified models, which only use simple geometric shapes, such as cubes and cylinders, to represent buildings and structures. However, to have more accurate and complete evaluation results, various shapes of blocking objects, such as trees, should also be taken into consideration. The aerodynamic effects of these various shapes of objects can decrease wind velocity and increase turbulence intensity. Previous studies simply omitted the errors generated from these various shapes of blocking objects. Adding real geometrical trees to the numerical models makes the calculating domain of CFD very complicated due to geometry generation and grid meshing problems. In this case the function of Porous Media Condition can solve the problem by adding trees into numerical models without increasing the mesh grids. The comparison results between numerical and wind tunnel model are close if the parameters of porous media condition are well adjusted.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1333-1343
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• 2016

Spectrum sharing in centrally controlled cognitive radio (CR) networks has been widely studied, however, research on channel access for distributively controlled individual cognitive users has not been fully characterized. This paper conducts an analysis of random channel access of cognitive users controlled in a distributed manner in a CR network. Based on the proposed estimation method, each cognitive user can estimate the current channel condition by using its own Markov-chain model and can compute its own blocking probability, collision probability, and forced termination probability. Using the proposed scheme, CR with distributed control (CR-DC), CR devices can make self-controlled decisions based on the status estimations to adaptively control its system parameters to communicate better.

• Korean Membrane Journal
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• v.5 no.1
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• pp.31-35
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• 2003

The permeation characteristics of the wastewater containing Si fine particles were examined by ultrafiltration using the polyolefin tubular membrane module. Flux with time was due to the growth of Si cake deposited on the membrane surface and the pore plugging by fine particles. The rate of flux decline in the initial stage increased with the trans-membrane pressure. The pore blocking resistance was the dominant resistance at the initial period of filtration and the cake resistance began to dominate with the initial pore blocking resistance. The larger pores compared with the fine particles, the more the membrane pores could be blocked by the fine particles. Before and after treatment, the distribution of particle size was shifted toward to the left. Then, the average size of fine particles in the permeate was 20 nm.

• Journal of the Korean Ceramic Society
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• v.54 no.5
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• pp.413-421
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• 2017

In this work, we studied a fluorite structure oxides: Yttria stabilized zirconia, (YSZ); Gd doped $CeO_2$ (GDC); erbia stabilized $Bi_2O_3$ (ESB); Zr doped erbia stabilized $Bi_2O_3$ (ZESB); Ca doped erbia stabilized $Bi_2O_3$ (CESB) in the temperature range of 250 to $600^{\circ}C$ using electrochemical impedance spectroscopy (EIS). As is well known, grain boundary blocking effect was observed in YSZ and GDC. However, there is no grain boundary effect on ESB, ZESB, and CESB. The Nyquist plots of these materials exhibit a single arc at low temperature. This means that there is no space charge effect on ${\delta}-Bi_2O_3$. In addition, impedance data were analyzed by using the brick layer model. We indirectly demonstrate that grain boundary ionic conductivity is similar to or even higher than bulk ionic conductivity on cubic bismuth oxide.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2644-2652
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• 1997

We ivestigate a two-stage queueing system which frequently arises in the study of overflow problems. A primary service facility consists of multiple primary queues where blocked calls are overflowed to a secondary queue. By approximating the input to the secondary queue with a two-state Markov Modulated Poisson Process (MMPP), we derive the blocking probability of the secondary queue. For the approximation, we employ the well-known Heffes' method and the SAM procedure.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.1
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• pp.9-15
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• 2011

Highly pathogenic avian influenza could not be identified visually. It takes time to identify the symptoms by its incubation period. Without taking a quick step, the diffusion area of HPAI has dramatically increased, the extent of damage becomes bigger. In network research, the algorithm of finding the central node on the network applied to various diffusion of epidemic problems, was used in control system of tracing the diffusion path, blocking central nodes. This study tried to make the diffusion of HPAI network model for the crowded farms area, and reduce the diffusion rate to control the high-risk farms.

• BMB Reports
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• v.50 no.8
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• pp.417-422
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• 2017

Cisplatin is the most effective and widely used chemotherapeutic agent for many types of cancer. Unfortunately, its clinical use is limited by its adverse effects, notably bone marrow suppression leading to abnormal hematopoiesis. We previously revealed that neuropeptide Y (NPY) is responsible for the maintenance of hematopoietic stem cell (HSC) function by protecting the sympathetic nervous system (SNS) fibers survival from chemotherapy-induced bone marrow impairment. Here, we show the NPY-mediated protective effect against bone marrow dysfunction due to cisplatin in an ovarian cancer mouse model. During chemotherapy, NPY mitigates reduction in HSC abundance and destruction of SNS fibers in the bone marrow without blocking the anticancer efficacy of cisplatin, and it results in the restoration of blood cells and amelioration of sensory neuropathy. Therefore, these results suggest that NPY can be used as a potentially effective agent to improve bone marrow dysfunction during cisplatin-based cancer therapy.