• The Journal of Engineering Research
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• v.3 no.1
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• pp.117-121
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• 1998

This paper describes a model suitable for real-time languages, which explicitly defines a set of resource objects. The resource objects are constituted in a specialization hierarchy which allows programmers to perform resource handling at any desired level of detail, as well as providing a uniform interface. This object-oriented model is used to extend the applicability of the imprecise computation approach to deal with shortfalls of any computational resource, and enable to build real-time systems which can handle dynamic situations.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.406-409
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• 2008

Clustering data streams has an importance over many applications like sensor networks. Existing hierarchical methods follow a semi fuzzy clustering that yields duplicate clusters. In order to solve the problems, we propose an extended online divisive agglomerative clustering on data streams. It builds a tree-like top-down hierarchy of clusters that evolves with data streams using geometric time frame for snapshots. It is an enhancement of the Online Divisive Agglomerative Clustering (ODAC) with a pruning strategy to avoid duplicate clusters. Our main features are providing update time and memory space which is independent of the number of examples on data streams. It can be utilized for clustering sensor data and network monitoring as well as web click streams.

• Management Science and Financial Engineering
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• v.9 no.1
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• pp.11-27
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• 2003

In this study, we propose a mathematical model based on the graph theory for the wavelength assignment problem arising in the design of SDH (Synchronous Digital Hierarchy) over WDM (Wavelength Division Multiplexing) ring networks. We propose a branch- and -price algorithm to solve the suggested models effectively within reasonable time in realistic SDH over WDM ring networks. By exploiting the structure of ring networks, we developed a polynomial time algorithm for efficient column generation and a branching rule that conserves the structure of column generation. In a computer simulation study, the suggested approach can find the optimal solutions within reasonable time and show better performance than the existing heuristics.

• Journal of Cadastre & Land InformatiX
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• v.52 no.2
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• pp.17-34
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• 2022

With rapid advancements taking place in the Fourth Industrial Revolution, human-robot interactions have been garnering increasing attention. Robots are being actively adopted in building systems and facilities. In this study, we developed robot-friendly building certification indicators. Because these indicators were being developed for the first time, we focused only on commercial buildings. We conducted exploratory research using methodologies such as focus group interviews and the analytic hierarchy process. First, the concept of the robot-friendly building was defined through focus group interviews, and the requirements were categorized by the appropriateness of operating facilities and systems and the appropriateness of architectural and robot operating systems and networks. Next, the relative importance of the evaluation items (23 items in total) was calculated using the analytic hierarchy process. Their average score of the marks was 4.4, and the minimum and maximum were 2.0 and 11.3, respectively. This study is significant because we collected the basic data necessary to develop a one-of-its-kind evaluation system for certifying the robot-friendliness of buildings using scientific methods.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.2
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• pp.150-156
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• 2008

Many papers have shown that the hierarchical clustering method takes good-performance, but is limited because of its quadratic time complexity. In contrast, with a large number of variables, K-means reduces a time complexity. Think of the factor of simplify, high-quality and high-efficiency, we combine the two approaches providing a new system named CONDOR system with hierarchical structure based on document clustering using K-means algorithm. Evaluated the performance on different hierarchy depth and initial uncertain centroid number based on variational relative document amount correspond to given queries. Comparing with regular method that the initial centroids have been established in advance, our method performance has been improved a lot.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.6_1
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• pp.549-557
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• 2012

Spatial phenomena such as environment pollution, disease and the risk of spreading information need a rapid initial response to perceive spread event. Moving data perceive spread event through real-time processing and analysis. To process and analysis the event, spatial-temporal complex event processing is used. Previous spatialtemporal complex event processing is possible basis spatial operator but insufficient apply to design spatialtemporal complex event processing to perceive spatial phenomena of high complexity. This study proposed hierarchical spatio-temporal CEP design which will efficiently manage the fast growing incoming sensor data. The implementation of the proposed design is evaluated with GPS location data of moving vehicles which are used as the incoming data stream for identifying spatial events. The spatial component of existing CEP software engine has been extended during the implementation phase to broaden the capabilities of processing spatio-temporal events.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.103-113
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• 2006

The purpose of this study was to evaluate an effect of the new air traffic control display designed by Ecological Interface Design [EID]. The methodology of EID has not been applied to the development of the air traffic control display so far. To design a new air traffic control display by EID, We implemented Work Domain Analysis about the air traffic control domain and made the Work Domain Model that consisted of the five levels of the Abstraction Hierarchy. We extracted the Information Requirement from the completed Work Domain Model and the extracted information requirements from the model were used to design the new air traffic control display. We evaluated an effect of the new air traffic control display designed by EID. Participants for evaluating consisted of 14 active military air traffic controller of the Republic of Korea Air Force. Experiment was designed two factors within subject. Factors manipulated in the experiment included displays type to compare the existing type with the new ecological interface type and included complexity to compare the effect of the high complex situation with the effect of the low complex situation. Response time about questions with relation to air traffic collision situation, accuracy, and subjective work load were measured. The results reveled that EID type's display has a significant effect on response time, accuracy, and subjective work load and verified that EID could be applied to the air traffic control domain that is more complex and dynamic.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.45-54
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• 2005

The existing access control models have the demerits that do not provide the limit function of using resources by time constraint, the restricted inheritance function as a superior role in role hierarchy, the delicate delegation policy and the limit function of using resources by the location information about a user for the access control in ubiquitous environment. This paper proposes an Extended-GTRBAC model is suited to the access control in ubiquitous environment by applying to sub-role concept of GTRBAC model that the application of resources can be restricted by the period and time and PBDM and considering the location information about a user on temporal constraint. The proposal model can restrict the inheritance of permission in role hierarchy by using sub-role, provide the delicate delegation policy such as user-to-user delegation, role to role delegation, multi-level delegation. multi-step delegation, and apply diverse and delicate access control policy which is suited the characteristic of ubiquitous environment by considering the location information about a user on temporal constraint.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2B
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• pp.76-81
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• 2008

LEACH (Low Energy Adaptive Clustering Hierarchy) has been proposed as a routing protocol with a hierarchical structure, in order to achieve the energy efficiency that is of primary importance in the wireless sensor networks. A wireless sensor network adopting LEACH is composed of a few clusters, each of which consists of member nodes that sense the data, and head nodes that deliver the collected data from member nodes to a sink node that is connected to a backbone network. A head node in a cluster allocates TDMA slots to its member nodes without taking into account whether they have data to transmit or not, thus resulting in inefficiency of energy usage of head node that remains in active mode during the entire round time. This motivates us to propose a scheme to improve the energy efficiency of LEACH, by assigning TDMA slots only to those member nodes who have data to send. As a result, the head node can remain sleep during the period of no data transmission from member nodes, leading to the substantial energy saving. By using the ns-2 simulator, we evaluate the performance of the proposed scheme in comparison with the original LEACH. Experimental results validate our scheme, showing a better performance than original LEACH in terms of the number of outliving nodes and the quantity of energy consumption as time evolves.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2D
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• pp.311-318
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• 2009

Interactive terrain visualization is an important research area with applications in GIS, games, virtual reality, scientific visualization and flight simulators, besides having military use. This is a complex and challenging problem considering that some applications require precise visualizations of huge data sets at real-time rates. In general, the size of data sets makes rendering at real-time difficult since the terrain data cannot fit entirely in memory. In this paper, we suggest the effective Real-time LOD(level-of-detail) algorithm for displaying the huge terrain data and processing mass geometry. We used a hierarchy structure with $4{\times}4$ and $2{\times}2$ tiles for real-time rendering of mass volume DEM which acquired from Digital map, LiDAR, DTM and DSM. Moreover, texture mapping is performed to visualize realistically while displaying height data of normalized Giga Byte level with user oriented terrain information and creating hill shade map using height data to hierarchy tile structure of file type. Large volume of terrain data was transformed to LOD data for real time visualization. This paper show the new LOD algorithm for seamless visualization, high quality, minimize the data loss and maximize the frame speed.