• The Korean Journal of Applied Statistics
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• v.33 no.4
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• pp.511-526
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• 2020

Single-cell RNA-sequencing (scRNA-seq) data consists of each cell's RNA expression extracted from large populations of cells. One main purpose of using scRNA-seq data is to identify inter-cellular heterogeneity. However, scRNA-seq data pose statistical challenges when applying traditional clustering methods because they have many missing values and high level of noise due to technical and sampling issues. In this paper, motivated by analyzing scRNA-seq data, we propose a novel spectral-based clustering method by imposing different weights on genes when computing a similarity between cells. Assigning weights on genes and clustering cells are performed simultaneously in the proposed clustering framework. We solve the proposed non-convex optimization using an iterative algorithm. Both real data application and simulation study suggest that the proposed clustering method better identifies underlying clusters compared with existing clustering methods.

• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.259-269
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• 2013

This study aims to show the feasibility of wastewater reuse through hydrological analysis and propose a framework for planning using multi-criteria decision making technique. Ten alternatives of wastewater reuse (BOD: 3.0 mg/L & 4.7 mg/L) and two references in the urban watershed were considered and analyzed by using Hydrological Simulation Program in Fortran (HSPF). Though wastewater reuse has a positive effect on water quantity, it may degrade the water quality due to the high discharge concentration. This study showed that wastewater reuse can be a great alternative for the rehabilitation of distorted water cycle, if the quality is improved up to the natural streamflow and the quantity is increased up to the instreamflow requirement. In addition, to determine the project priority, three criteria were compared: 1) impacts on water quantity and water quality, respectively, 2) consideration of present hydrologic vulnerabilities on water quantity and quality and not, and 3) social and economic considerations and not. From the performance values to all criteria, the specific ranking can be derived and the feasibility of each wastewater reuse project can be checked with the comparison of the existing facilities. As a result, DJ and DR were derived to become effective in any evaluation conditions while SS and WG were improper alternatives if various criteria were considered. The decision making for project prioritization must be careful with the consideration of various impacts of wastewater reuse because the evaluation of wastewater reuse alternative showed very different priorities for each criteria.

• Korean Journal of Cognitive Science
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• v.10 no.4
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• pp.71-83
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• 1999

Conventional symbolic inference systems lack flexibility because they do not well reflect flexible semantic structure of knowledge and use symbolic logic for their basic inference mechanism. For solving this problem. we have recently proposed the 'Connectionist Semantic Network(CSN)' as a model for flexible knowledge representation and inference based on neural networks. The CSN is capable of carrying out both approximate reasoning and commonsense reasoning based on similarity and association. However. we have difficulties in representing general and structured high-level knowledge and variable binding using the connectionist framework of the CSN. In this paper. we propose a hybrid system called SymCSN(Symbolic CSN) that combines a symbolic module for representing general and structured high-level knowledge and a connectionist module for representing and learning low-level semantic structure Simulation results show that the SymCSN is a plausible model for human-like flexible knowledge representation and inference.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.1
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• pp.10-18
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• 2007

In this paper, we extend the multiple time scale control framework to window-based congestion control, in particular, TCP. This is performed by interfacing TCP with a large time scale control module which adjusts the aggressiveness of bandwidth consumption behavior exhibited by TCP as a function of "large time scale" network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by RTT. Performance evaluation of multiple time scale TCP is facilitated by a simulation bench-mark environment which is based on physical modeling of self-similar traffic. If source traffic is not extended exceeding, when RTT is 450ms, in self similar burst environment, performance gain of TCP-SSC is up to 45% for ${\alpha}$=1.05. However, its is acquired only 20% performance gain for ${\alpha}$=1.95 relatively. Therefore we showed that by TCP-MTS at large time scale into a rate-based feedback congestion control, we are able to improve two times performance significantly.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1640-1651
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• 2009

In this paper we introduce a new approach to stroke based rendering using brush stroke profile. Our proposed method, based on image retrieval method, is a simple but flexible and scalable method to create various painting styles, for which scalable database constructed with the collection of real stroke data is used. Input image is reproduced with combinations of brush stoke in the database, when a search process to determinate appropriate brush stroke and a judgment process to decide whether to draw the retrieved brush stroke on the canvas or not are presented. In addition, this paper suggests a new brush stroke model and a depiction technique in order to utilize effective height information which allows natural texture depiction, or good visual effect, without carrying out physical simulation. Our method is able to create diverse variations of painting by controling various user parameters. It also provides scalable framework that can produce various painting styles with different artistic media by changing the stroke combinations of stroke database.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.118-126
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• 2007

An ad hoc network is a system of wireless mobile nodes that dynamically self-organize in arbitrary and temporary network topologies allowing people and devices to internetwork without any preexisting communication infrastructure. Although ad hoc network is attractive solution, there are still some major flaws that prevent commercial growth. Security is one of these main barriers; ad hoc networks are known to be particularly vulnerable to security attack. It is difficult to establish a centralized key distribution center and a trusted certification authority to provide cryptographic keys and digital certificates to nodes. To prevent attacks in ad hoc routing protocols, many algorithms have been used. In this paper, we have depicted a secure framework for multipath routing in wireless multihop network, which is comprehensive solution for secure data forwarding in wireless multihop networks. With the simulation results, the proposed scheme is compared with existing source routing scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4B
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• pp.207-214
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• 2008

Under future internet environment, wireless sensor networks will be used in a wide range of applications. A major problem for designing sensor protocol is developing the most energy efficient technique to monitor an area of interest for a long time since sensors have some constraints such as small and a limited energy level. In addition, data latency is often a critical issue since sensory data is transmitted via multi hop fashion and need to be delivered timely for taking an appropriate action. Our motivation for designing a data forwarding protocol is to minimize energy consumption while keeping data latency bound in wireless sensor networks. In this paper, we propose a data forwarding protocol that consists of wakeup scheduling and MAC protocols, the latter of which is designed to achieve load balancing. Simulation results show that the proposed framework provides more energy-efficient delivery than other protocol.

• Journal of The Korea Institute of Healthcare Architecture
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• v.19 no.4
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• pp.7-18
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• 2013

Purpose: The aim of this paper is to reduce the stress and the disturbance occur in selective action of patient. This article will also help us to control spreading and reduce the order and bacteria produced by leprosy disease among the lepers. This will be achieved with the help of several variables and these variables help us on health benefits is 5S (Sort, Straighten, Shine, Standardize, Sustain) i.e. ratio of sectional morphology, lessor 90 degree angles, day light, universal design building and maximum ventilation. The replies from the questionnaire were collected based on varying levels of satisfaction and gloominess on the scale of 1-10. Methods: The multi-layer methodological framework for maximising the healing environment obtained from the observation of schemes and parameters of ANOVA: (Analysis Of Variance between five deciding factors) are. Firstly applied for the calculation of the patient's satisfaction for U.V light from sun on ECOTECT simulation, secondly the number of $90^{\circ}$ angle, along the corridors. Thirdly understanding the ways to represent people's perceptual structures and way finding with Space Syntax software. Fourthly the ratio of depth to height of the building typology and finally interviewing the subjects describing their special experiences based on scale value. The focus of this testing of human subjects was to receive data for the existence of image scheme in way-finding and to identify the mechanisms by which sun light impacts human (lepers) health. Results: AMPVA studies concluded that there is similarity between I and O plan as well as L and H plan whereas U plan was difference among the five selected architectural shapes. Implications: The purpose of this research is to show the effects of the I-type, L-type, C-type, U-type and O-type plan design, and to analyse the morphology for EBD (Evidence-Based Design) healing environment which is a universal design for Munghopir Karachi, in Pakistan.

• Journal of the Korean Society of Safety
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• v.35 no.2
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• pp.100-110
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• 2020

Recently, the frequency of typhoon and torrential rain due to climate change is increasing. In addition, the upsurge in the complexity of urban sewer network and impervious surfaces area aggravates the inland flooding damage. In response to these worsening situations, the central and local governments are conducting R&D tasks related to predict and mitigate the flood risk. Researches on the analysis of inundation in urban areas have been implemented through various ways, and the common features were to evaluate the accuracy and justification of the model by comparing the model results with the actual inundation data. However, the evaluation procesure using available urban flooding data are not consistent, and if there are no quantitative urban inundation data, verification has to be performed by using press releases, public complaints, or photos of inundation occurring through 'CCTV'. Because theses materials are not quantitative, there is a problem of low reliability. Therefore, this study intends to develop a comparative analysis procedure on the quantitative degree and applicability of the verifiable inundation data, and a systematic framework for the performance assessment of urban flood analysis model was proposed. This would contribute to the standardization of the evaluation and verification procedure for urban flooding modelling.

• Journal of Intelligence and Information Systems
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• v.11 no.3
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• pp.1-23
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• 2005

Personalized reminder systems have to identify the user's current needs dynamically and proactively based on the user's current context. However, need identification methodologies and their feasible architectures for personalized reminder systems have been so far rare. Hence, this paper aims to propose a proactive need awaring mechanism by applying agent, semantic web technologies and RFID-based context subsystem for a personalized reminder system which is one of the supporting systems for a robust ubiquitous service support environment. RescorlaWagner model is adopted as an underlying need awaring theory. We have created a prototype system called NAMA(Need Aware Multi-Agent)-RFID, to demonstrate the feasibility of the methodology and of the mobile settings framework that we propose in this paper. NAMA considers the context, user profile with preferences, and information about currently available services, to discover the user's current needs and then link the user to a set of services, which are implemented as web services. Moreover, to test if the proposed system works in terms of scalability, a simulation was performed and the results are described.