• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1905-1919
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• 2000

The main motivation of this research is to develop an intelligent control strategy for Activated Sludge Process (ASP). ASP is a complex and nonlinear dynamic system because of the characteristic of wastewater, the change in influent flow rate, weather conditions, and etc. The mathematical model of ASP also includes uncertainties which are ignored or not considered by process engineer or controller designer. The ASP is generally controlled by a PID controller that consists of fixed proportional, integral, and derivative gain values. The PID gains are adjusted by the expert who has much experience in the ASP. The ASP model based on $Matlab^{(R)}5.3/Simulink^{(R)}3.0$ is developed in this paper. The performance of the model is tested by IWA(International Water Association) and COST(European Cooperation in the field of Scientific and Technical Research) data that include steady-state results during 14 days. The advantage of the developed model is that the user can easily modify or change the controller by the help of the graphical user interface. The ASP model as a typical nonlinear system can be used to simulate and test the proposed controller for an educational purpose. Various control methods are applied to the ASP model and the control results are compared to apply the proposed intelligent control strategy to a real ASP. Three control methods are designed and tested: conventional PID controller, fuzzy logic control approach to modify setpoints, and fuzzy-PID control method. The proposed setpoints changer based on the fuzzy logic shows a better performance and robustness under disturbances. The objective function can be defined and included in the proposed control strategy to improve the effluent water quality and to reduce the operating cost in a real ASP.

• Journal of Intelligence and Information Systems
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• v.27 no.4
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• pp.49-71
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• 2021

Users who intend to utilize knowledge to actively solve given problems proceed their jobs with cross- and sequential exploration of associated knowledge related each other in terms of certain criteria, such as content relevance. A knowledge map is the diagram or taxonomy overviewing status of currently managed knowledge in a knowledge-base, and supports users' knowledge exploration based on certain relationships between knowledge. A knowledge map, therefore, must be expressed in a networked form by linking related knowledge based on certain types of relationships, and should be implemented by deploying proper technologies or tools specialized in defining and inferring them. To meet this end, this study suggests a methodology for developing the knowledge graph-based knowledge map using the Graph DB known to exhibit proper functionality in expressing and inferring relationships between entities and their relationships stored in a knowledge-base. Procedures of the proposed methodology are modeling graph data, creating nodes, properties, relationships, and composing knowledge networks by combining identified links between knowledge. Among various Graph DBs, the Neo4j is used in this study for its high credibility and applicability through wide and various application cases. To examine the validity of the proposed methodology, a knowledge graph-based knowledge map is implemented deploying the Graph DB, and a performance comparison test is performed, by applying previous research's data to check whether this study's knowledge map can yield the same level of performance as the previous one did. Previous research's case is concerned with building a process-based knowledge map using the ontology technology, which identifies links between related knowledge based on the sequences of tasks producing or being activated by knowledge. In other words, since a task not only is activated by knowledge as an input but also produces knowledge as an output, input and output knowledge are linked as a flow by the task. Also since a business process is composed of affiliated tasks to fulfill the purpose of the process, the knowledge networks within a business process can be concluded by the sequences of the tasks composing the process. Therefore, using the Neo4j, considered process, task, and knowledge as well as the relationships among them are defined as nodes and relationships so that knowledge links can be identified based on the sequences of tasks. The resultant knowledge network by aggregating identified knowledge links is the knowledge map equipping functionality as a knowledge graph, and therefore its performance needs to be tested whether it meets the level of previous research's validation results. The performance test examines two aspects, the correctness of knowledge links and the possibility of inferring new types of knowledge: the former is examined using 7 questions, and the latter is checked by extracting two new-typed knowledge. As a result, the knowledge map constructed through the proposed methodology has showed the same level of performance as the previous one, and processed knowledge definition as well as knowledge relationship inference in a more efficient manner. Furthermore, comparing to the previous research's ontology-based approach, this study's Graph DB-based approach has also showed more beneficial functionality in intensively managing only the knowledge of interest, dynamically defining knowledge and relationships by reflecting various meanings from situations to purposes, agilely inferring knowledge and relationships through Cypher-based query, and easily creating a new relationship by aggregating existing ones, etc. This study's artifacts can be applied to implement the user-friendly function of knowledge exploration reflecting user's cognitive process toward associated knowledge, and can further underpin the development of an intelligent knowledge-base expanding autonomously through the discovery of new knowledge and their relationships by inference. This study, moreover than these, has an instant effect on implementing the networked knowledge map essential to satisfying contemporary users eagerly excavating the way to find proper knowledge to use.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.333-339
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• 2016

Technology to optimize and utilize the use and supply of the electric power between consumer and supplier has been on the rise among the smart grid power market network in electric power demand management based on the Internet. Open Automated Demand Response system protocol, which can deliver Demand Response needed in electric power demand management to electricity supplier, system supplier and even the user is openADR 2.0b. This paper used the most credible, cosmopolitanly proliferated EPRI open source and analysed the variety of security vulnerability that developed VEN and VTN system may have. Using the simulator for attacking openADR protocol, the VEN/VTN system that has been implemented as EPRI open source was conducted to attack in a variety of ways. As a result of the analysis, we were able to get the results that the VEN/VTN system has security vulnerabilities to the parameter tampering attacks and service flow falsification attack. In conclusion, if you want to implement the openADR2.0b protocol system in the open or two-way communication environment smart grid network, considering a variety of security vulnerability should be sure to seek security technology and services.

• Journal of Digital Contents Society
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• v.14 no.4
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• pp.557-564
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• 2013

An important research challenge about the traditional Internet environment is to enable open networking architecture on which end users are able to innovate the Internet based on the technologies of network programmability, virtualization, and federation. The SDN (Software Defined Network) technology that includes OpenFlow protocol specifications, is suggested as a major driver for the open networking architecture, and is closely coupled with the classical Internet (non-SDN). Therefore, it is very important to keep the integrated SDN and non-SDN network infrastructure reliable from the view point of network operators and engineers. Under this background, this paper proposes an operations and management framework for the combined software defined network environment across not only a single-domain network, but also multi-domain networks. The suggested framework is designed to allow SDN controllers and DvNOC systems to interact with each other to achieve sustainable end-to-end user-oriented SDN and non-SDN integrated network environment. Plus, the proposed scheme is designed to apply enhanced functionalities on DvNOC to support four major network failure scenarios over the combined network infrastructure, mainly derived from SDN controllers, SDN devices, and the connected network paths.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.130-145
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• 2016

Soil erosion processes are affected by weather factors, such as rainfall, temperature, wind, and humidity. Among these factors, rainfall directly influences soil erosion by breaking away soil particles. The kinetic energy of rainfall and water flow caused by rain entrains and transports soil particles downstream. Therefore, in order to estimate soil erosion, it is important to accurately determine the rainfall erosivity factor(R) in RUSLE(Revised Universal Soil Loss Equation). The objective of this study is to evaluate the average annual R using 14 years(2002~2015) of 1 minute rainfall data from 55 KMA(Korea Meteorological Administration) weather stations. The R results from 1 min rainfall were compared with previous R studies using 1 h rainfall data. The determination coefficients($R^2$) between R calculated using 1 min rainfall data and annual rainfall were 0.70-0.98. The estimation of 30 min rainfall intensity from 1 min rainfall data showed better $R^2$ results than results from 1 h rainfall data. For estimation of physical spatial rain erosivity(R), distribution of annual rainfall was estimated by IDW(Inverse Distance Weights) interpolation, taking elevation into consideration. Because of the computation burden, the R calculation process was programmed using the python GUI(Graphical User Interface) tool.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.1
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• pp.27-38
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• 2009

The multi-level profile system is designed to measure the vertical profile of $H_2O$ and $CO_2$ concentrations in the surface layer to estimate the storage effects within the plant canopy. It is suitable for long-term experiments and can be used also in advection studies for estimating the spatial variability and vertical gradients in concentration. It enables the user to calculate vertical fluxes of water vapor, $CO_2$ and other trace gases using the surface layer similarity theory and to infer their sources or sinks. The profile system described in this report includes the following components: sampling system, calibration and flow control system, closed path infrared gas analyzer(IRGA), vacuum pump and a datalogger. The sampling system draws air from 8 inlets into the IRGA in a sequence, so that for 80 seconds air from all levels is measured. The calibration system, controlled by the datalogger, compensates for any deviations in the calibration of the IRGA by using gas sources with known concentrations. The datalogger switches the corresponding valves, measures the linearized voltages from the IRGA, calculates the concentrations for each monitoring level, performs statistical analysis and stores the final data. All critical components are mounted in an environmental enclosure and can operate with little maintenance over long periods of time. This report, as a practical manual, is designed to provide helpful information for those who are interested in using profile system to measure evapotranspiration and net ecosystem exchanges in complex terrain.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.897-905
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• 2015

This research suggested the traffic signal calculation model of active transit signal priority using a shockwave model. Using this signal priority timing optimization model, the shockwave area is computed under the condition of Early Green and Green Extension among active transit signal priority techniques. This study suggested the speed estimation method of backward shockwave using average travel time and intersection passing time. A shockwave area change is calculated according to signal timing change of transit signal priority. Moreover, this signal timing calculation model could determine the optimal signal priority timings to minimize intersection delay of general vehicles. A micro simulation analysis using VISSIM and its user application model ComInterface was applied. This study checked that this model could calculate the signal timings to minimize intersection delay considering saturation condition of traffic flow. In case studies using an isolated intersection, this study checked that this model could improve general vehicle delay of more over ten percentage as compared with equality reduction strategy of non-priority phases. Recently, transit priority facilities are spreading such as tram, BRT and median bus lane in Korea. This research has an important significance in that the proposed priority model is a new methodology that improve operation efficiency of signal intersection.

• Economic and Environmental Geology
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• v.40 no.4
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• pp.419-443
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• 2007

Recently, the branch-out of foreign companies into domestic markets through M&A and the opened followed by the Free Trade Agreement(FTA) with America have made the environmental site assessments of specific site more necessary. In this study, through case study of conducting actual environmental site assessment by use of a toolbox approach at a large scale of chemical plant with various contaminants located in a coastal area, the problems of guideline of domestic environmental assessment of soil were complemented. And an efficient and economical assessment was achieved. All six steps such as basic investigation, environmental site history survey, sampling and analysis, installation of monitoring wells and hydrogeological survey, and data interpretation were conducted in this study. All results of document survey, geological lineament analysis, field geology survey of surrounding area, geophysical prospecting of the site, hydraulic conductivity, measurement of groundwater flow rate and direction, sampling and analysis at each step were associated and estimated as an integrated tool box approach. As a consequence of this study, toolbox approaches were very useful techniques for contamination level and site characterization of subsurface media. The given conditions to conduct a basic survey for domestic soil environment assessment of site by use of existing documents, as well as interviews with the owner/manager/user of all adjacent properties and thorough review of all practically reviewable records pertaining to the property and surrounding properties within "Guideline for Soil Environment Assessment" radii are very poor. As a result, the application of toolbox approach in the environment site assessment of site is not only more efficient and economical, but also could be very useful assessment to integrate the soil and groundwater contamination.

• Korean Institute of Interior Design Journal
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• v.22 no.4
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• pp.23-32
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• 2013

This study represents something in common and differences of organic characteristics between early modern architecture and contemporary architecture analysing F. L. Wright's Robie House and Toyo Ito's Sendai Mediatheque. A natural organic body cannot be separated from the natural environment, and each part of an architecture has each own property and forms a whole at the same time. That is a basic concept of organic architecture, and a framework for analysis is set up based on it. The followings are similarities and differences of organic concept and interpretation between Wright's Robie House and Ito's Sendai Mediatheque First, Wright' Robie house unites with the natural surrounding, using a physically close connection to the ground. In contract, Ito's Mediatheque shows characteristics of noncentural and fluidic space that are metaphorically reflecting tangible and intangible of factors in modern city, where there is an ambiguous physical boundary between architecture and urban environment. Next, floors, walls and ceilings of Wright's housing as for basic building blocks are physically separated and at the same time form formative unity from the point of view of a physical and structural organic body. And continuous flow of faces of separated walls form an organism united with the nature from a physical aspect. On the contrary to this, there is an no-boudary and floating organic architecture of integrated structure from ambiguous setting of relation between architecture and urban space in Ito's architecture. Especially, Mediatheque shows semantic integration of floating urban environmental factors through horizontal and vertical integration of horizontal slabs, vertical pipes, and skins. Last, horizontal and vertical factors of Wright' Housing is appreciated as an basic experienced structure in terms of spacial perception and fluidic inner spaces in Wright's housing is completed with a series of spatial experiences in a visual sense. On the other hand, no-boundary and floating space of Ito's architecture accept user's physical and virtual body. Especially, there is an integration transcending beyond time and space, accepting an imaginary body and events with the course of time at Ito's Mediatheque.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.171-179
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• 2008

RBAC(Role based Access Control) is effective way of managing user's access to information object in enterprise level and e-government system. The concept of RBAC is that the access right to object in a system is not directly assigned o users but assigned by being a member of a role which is defined in a organization. RBAC is utilized for controling access range of privacy but it does not support the personal legal right of control over information and right of limited access to the self. Nor it contains the way of observation of privacy flow that is guided in a legal level. In this paper, extended RBAC model for protecting privacy will be suggested and discussed. Two components of Data Right and Assigning Data Right are added to existed RBAC and the definition of each component is redefined in aspect of privacy preservation. Data Right in extended RBAC represents the access right to privacy data. This component provides the way of control over who can access which privacy and ensures limitation of access quantity of privacy. Based on this extended RBAC, implemented examples are presented and the evaluation is discussed by comparing existed RBAC with extended RBAC.