• Wind and Structures
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• v.22 no.6
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• pp.617-633
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• 2016

In this paper, the analysis of hyperbolic cooling tower on elastic subsoil exposed to unsymmetrical wind loading is presented. Modified Vlasov foundation model is used to determine the soil parameters as a function of vertical deformation profile within subsoil. The iterative parameter updating procedure involves the use of Open Application Programming Interface (OAPI) feature of SAP2000 to provide two way data flow during execution. A computing tool coded in MATLAB employing OAPI is used to perform the analysis of hyperbolic cooling tower with supporting columns over a hollow annular raft founded on elastic subsoil. The analysis of such complex soil-structure system is investigated under self-weight and unsymmetrical wind load. The response of the cooling tower on elastic subsoil is compared with that of a tower that its supporting raft foundation is treated as fixed at the base. The results show that the effect of subsoil on the behavior of cooling tower is considerable at the top and bottom of the wall as well as supporting columns and raft foundation. The application of a full-size cooling tower has demonstrated that the procedure is simple, fast and can easily be implemented in practice.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.5
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• pp.27-34
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• 2018

Concrete placed under hot weather condition suffers from larger slump loss, rapid moisture evaporation due to high air temperature. Proper measures for material, transportation and curing should be taken to prevent the quality deterioration of the concrete under hot weather condition. In Korea, Although the period of hot weather concrete in Korea occupies only 2 months, there are a lot of quality problems including plastic, drying shrinkage and cold joint. Therefore, the objective of this paper is to investigate and compare the temperature history and crack occurrence of the concrete, which was placed in the actual apartment house construction field under hot weather condition, in response to the application of surface covered curing blankets including PE film, single layer clear bubble sheet, white colored bubble sheet and aluminum metalized bubble sheet. Test results indicated that the application of white colored bubble sheet and aluminum metalized bubble sheet showed most favorable results in terms of reduction in temperature rise and crack occurrence as well as easiness in handling. But, due to light reflection by aluminum metalized bubble sheet, it is believed that white colored bubble sheet is preferable.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3619-3637
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• 2022

Big data analytics offers endless opportunities for operational enhancement by extracting valuable insights from complex voluminous data. Hadoop is a comprehensive technological suite which offers solutions for the large scale storage and computing needs of Big data. The performance of Hadoop is closely tied with its configuration settings which depends on the cluster capacity and the application profile. Since Hadoop has over 190 configuration parameters, tuning them to gain optimal application performance is a daunting challenge. Our approach is to extract a subset of impactful parameters from which the performance enhancing sub-optimal configuration is then narrowed down. This paper presents a statistical model to analyze the significance of the effect of Hadoop parameters on a variety of performance metrics. Our model decomposes the total observed performance variation and ascribes them to the main parameters, their interaction effects and noise factors. The method clearly segregates impactful parameters from the rest. The configuration setting determined by our methodology has reduced the Job completion time by 22%, resource utilization in terms of memory and CPU by 15% and 12% respectively, the number of killed Maps by 50% and Disk spillage by 23%. The proposed technique can be leveraged to ease the configuration tuning task of any Hadoop cluster despite the differences in the underlying infrastructure and the application running on it.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.19-26
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• 2006

Recently, web server hacking is trending toward web application hacking which uses comparatively vulnerable web applications based on open sources. And, it is possible to hack databases using web interfaces because web servers are usually connected databases. Web application attacks use vulnerabilities not in web server itself, but in web application structure, logical error and code error. It is difficult to defend web applications from various attacks by only using pattern matching detection method and code modification. In this paper, we propose a method to secure the web applications based on profiling which can detect and filter out abnormal web application requests.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.108-113
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• 2006

Urban conditions, such as existing underground facilities and ambient noise due to cultural activity, restrict the general application of conventional geophysical techniques. At a tunnelling site in an urban area along an existing railroad, we used the refraction microtremor (REMI) technique (Louie, 2001) as an alternative way to get geotechnical information. The REMI method uses ambient noise recorded by standard refraction equipment and a linear geophone array to derive a shear-wave velocity profile. In the inversion procedure, the Rayleigh wave dispersion curve is picked from a wavefield transformation, and iteratively modelled to get the S-wave velocity structure. The REMI survey was carried out along the line of the planned railway tunnel. At this site vibrations from trains and cars provided strong seismic sources that allowed REMI to be very effective. The objective of the survey was to evaluate the rock mass rating (RMR), using shear-wave velocity information from REMI. First, the relation between uniaxial compressive strength, which is a component of the RMR, and shear-wave velocity from laboratory tests was studied to learn whether shear-wave velocity and RMR are closely related. Then Suspension PS (SPS) logging was performed in selected boreholes along the profile, in order to draw out the quantitative relation between the shear-wave velocity from SPS logging and the RMR determined from inspection of core from the same boreholes. In these tests, shear-wave velocity showed fairly good correlation with RMR. A good relation between shear-wave velocity from REMI and RMR could be obtained, so it is possible to estimate the RMR of the entire profile for use in design of the underground tunnel.

• Journal of KIISE:Software and Applications
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• v.33 no.1
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• pp.105-113
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• 2006

In this paper we propose wear-UCAM, which is a toolkit for context-aware application model in wearable computing. As the rapid developments of mobile technologies and relevant technologies, the interests in wearable computer also become indispensible in both academic and industrial fields. However, there are few research activities on the application framework or toolkit for wearable computing. Hence, we suggest wear-UCAM as the development toolkit for wearable computing applications, where we focus on how to collect relevant user context, manage it, and provide services based on the recognized context. The proposed wear-UCAM includes the abstraction of context processing as well as independence among sensors and services with other components. For the sake of rapid prototyping of the proposed toolkit, we utilize PDA with wireless LAN as a wearable computer. The detail explanation of the implementation and its discussion are presented in this paper.

• Journal of KIISE:Software and Applications
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• v.34 no.3
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• pp.179-195
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• 2007

Traditional software development method is not suitable for Web application development because of characteristics of Web application such as frequent requirements change, different architectures and models and quick-to-market delivery. In this paper we propose a Web application development method adaptable to requirements change while we systematically model Web application using extended UML model. The metamodel is independent to specific languages and technologies because we define the metamodel using extended UML model. Proposed process is described by SPEM(Software Process Engineering Metamodel) profile. A process supporting tool execute and customize process. To model Web applications systematically and effectively, a navigation modeling and a component communication modeling tools are provided. In a case study, we show the usefulness of our process and model.

• Journal of Intelligence and Information Systems
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• v.17 no.2
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• pp.109-117
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• 2011

The exhibition industry, as technology-intensive, eco-friendly industry, contributes to regional and national development and enhancement of its image as well, if it joins cultural and tourist industry. Therefore, We need to revitalize the exhibition industry, as actively holding an exhibition event. However, to attract a number of exhibition audience, the work of enhancing audience satisfaction and awareness of value for participation should be prioritized after improving quality of service within exhibition hall. As one way to enhance the quality of service, it is thought that the way providing personalized service geared toward each audience is needed. that is, if audience avoids the complexity in exhibition space and it affords them service to enable effective time and space management, it will improve the satisfaction. All such personalized service affordable lets the audience's preference on the basis of each audience profile registered in advance online grasp. and Based on this information, it is provided with exhibition-related information suited their purpose that is the booth for the interesting audience, the shortest path to go to the booth and event via audience's smart phone. and it collects audience's reaction information, such as visiting the booth, participating the event through offered the information in this way and location information for the flow of movement, the present position so that it makes revision of existing each audience profile. After correcting the information, it extracts the individual's preference. hereunder, it provides recommend booth and event information. in other words, it provides optimal information for individual by amendment based on reaction information about recommending information built on basic profile. It provides personalized service dynamic and interactive with audience. This paper will be able to provide the most suitable information for each audience through circular and interactive structure and designed smart-phone application supportable for updating dynamic and interactive personalized service that is able to afford surrounding information in real time, as locating movement position through sensing. The proposed application collects user‘s context information and carrys information gathering function collecting the reaction about searched or provided information via sensing. and it also carrys information gathering function providing needed data for user in exhibition hall. In other words, it offers information about recommend booth of position foundation for user, location-based services of recommend booth and involves service providing detailed information for inside exhibition by using service of augmented reality, the map of whole exhibition as well. and it is also provided with SNS service that is able to keep information exchange besides intimacy. To provide this service, application is consisted of several module. first of all, it includes UNS identity module for sensing, and contain sensor information gathering module handling and collecting the perceived information through this module. Sensor information gathered like this transmits the information gathering server. and there is exhibition information interfacing with user and this module transmits to interesting information collection module through user's reaction besides interface. Interesting information collection module transmits collected information and If valid information out of the information gathering server that brings together sensing information and interesting information is sent to recommend server, the recommend server makes recommend information through inference with gathered valid information. If this server transmit by exhibition information process, exhibition information process module is provided with user by interface. Through this system it raises the dynamic, intelligent personalized service for user.

• Journal of Korean Port Research
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• v.11 no.2
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• pp.215-230
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• 1997

A number of ocean outfalls are located around coastal area over the United States and discharge primary treated effluent into deep water for efficient wastewater treatment. Two of them, the Sand Island and Honouliuli municipal wastewater outfalls, are located on the south coast of Oahu. There have been growing interests about the plume dynamics around the ocean outfalls since plume discharged from the multiport diffuser may have significant impacts on coastal communities and immediate consequence on public health. Among the studies of plume dynamics performed in the vicinity of both outfalls, Project MB-4 in the Mamala Bay Study recently made with the funding in the $ 9 million amount statistically dealt with the near-field behavior of the plumes at the Sand Island and Honouliuli outfalls. However, Project MB-4 predicted much higher surfacing frequency than the realistic value obtained by model studies by Oceanit Laboratories, Inc.. It is suggested that improvements should be made in the application of the plume model to more simulate the actual discharge characteristics and ocean conditions. In this study, it has been recommended that input parameters in plume models reflect realistic density profile over the entire water column since. in the previous Mamala Bay Study, the density profiles were measured at 5m depth increments extending from 13 to 63 m depth (the density profile on the upper portion of water column was not included, Roberts 1995). It is proved that the density stratification is the important parameter for the submergence of the plume. In this study, as one of the important parameters, plume rise and initial dilution reflecting the density profile over the entire water column have been taken into account for more reliable plume behavior description.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2C
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• pp.181-188
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• 2007

This paper proposed a watermark embedding/extracting method using CABAC(Context-based Adaptive Binary Arithmetic Coding) which is the entropy encoder for the main profile of MPEG-4 Part 10 H.264/AVC. This algorithm selects the blocks and the coefficients in a block on the bases of the contexts extracted from the relationship to the adjacent blocks and coefficients. A watermark bit is embedded without any modification of coefficient or with replacing the LSB(Least Significant Bit) of the coefficient with a watermark bit by considering both the absolute value of the selected coefficient and the watermark bit. Therefore, it makes it hard for an attacker to find out the watermarked locations. By selecting a few coefficients near the DC coefficient according to the contexts, this algorithm satisfies the robustness requirement. From the results from experiments with various kinds and various strengths of attacks the maximum error ratio of the extracted watermark was 5.02% in maximum, which makes certain that the proposed algorithm has very high level of robustness. Because it embeds the watermark during the context modeling and binarization process of CABAC, the additional amount of calculation for locating and selecting the coefficients to embed watermark is very small. Consequently, it is highly expected that it is very useful in the application area that the video must be compressed right after acquisition.