• Geomechanics and Engineering
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• 제1권1호
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• pp.17-34
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• 2009

There has been growing agreement that geotechnical reliability-based design (RBD) is necessary for establishing more advanced and integrated design system. In this study, resistance factors for LRFD pile design using CPT results were investigated for axially loaded driven piles. In order to address variability in design methodology, different CPT-based methods and load-settlement criteria, popular in practice, were selected and used for evaluation of resistance factors. A total of 32 data sets from 13 test sites were collected from the literature. In order to maintain the statistical consistency of the data sets, the characteristic pile load capacity was introduced in reliability analysis and evaluation of resistance factors. It was found that values of resistance factors considerably differ for different design methods, load-settlement criteria, and load capacity components. For the total resistance, resistance factors for LCPC method were higher than others, while those for Aoki-Velloso's and Philipponnat's methods were in similar ranges. In respect to load-settlement criteria, 0.1B and Chin's criteria produced higher resistance factors than DeBeer's and Davisson's criteria. Resistance factors for the base and shaft resistances were also presented and analyzed.

• KIEAE Journal
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• 제9권1호
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• pp.23-30
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• 2009

A lightcourt design is typically used to address issues concerning aesthetics, feeling, and mood. From the view point of environmental aspect, as an ecological shaft space, it plays a key role in controlling inner quality. In particularly, the lightcourt concept allows the exploitation of daylighting by bring natural light into the center of the building, thus eliminating dark deep spaces. Additionally, the lightcourt shades the inner space in summer. The amount of light available at the base of the lightcourt depends on a number of factors; translucency of the top, reflectance and the geometry of the space. In this paper is to exemplify a lightcourt configuration with a sloped wall. It promises the maximized a sense of freedom and daylighting availability. It is a matter of course that the lightcourt with open-top plays a role as a light source for the adjacent space to the lightcourt. A series of lighting simulation provides performance data of daylighting with changing photometric factors. For the case that a skylight is not available, an electric lighting design with metal halide lamps has been established to create luminous ceiling. As expected, a sloped lightcourt with open-top exposes its superiority of daylighting source. Ancillary considerations to enhance of daylighting potential for the adjacent space have been issued with performance data.

• Journal of Communications and Networks
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• 제18권2호
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• pp.173-181
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• 2016

In this paper, we address a new robust optimization problem in a multiuser multiple-input single-output broadcasting system with simultaneous wireless information and power transmission, where a multi-antenna base station (BS) sends energy and information simultaneously to multiple users equipped with a single antenna. Assuming that perfect channel-state information (CSI) for all channels is not available at the BS, the uncertainty of the CSI is modeled by an Euclidean ball-shaped uncertainty set. To optimally design transmit beamforming weights and receive power splitting, an average total transmit power minimization problem is investigated subject to the individual harvested power constraint and the received signal-to-interference-plus-noise ratio constraint at each user. Due to the channel uncertainty, the original problem becomes a homogeneous quadratically constrained quadratic problem, which is NP-hard. The original design problem is reformulated to a relaxed semidefinite program, and then two different approaches based on convex programming are proposed, which can be solved efficiently by the interior point algorithm. Numerical results are provided to validate the robustness of the proposed algorithms.

• Smart Structures and Systems
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• 제4권6호
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• pp.795-807
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• 2008

A challenging problem in structural damage detection based on vibration data is the requirement of a large number of sensors and the numerical difficulty in obtaining reasonably accurate results when the system is large. To address this issue, the substructure identification approach may be used. Due to practical limitations, the response data are not available at all degrees of freedom of the structure and the external excitations may not be measured (or available). In this paper, an adaptive damage tracking technique, referred to as the sequential nonlinear least-square estimation with unknown inputs and unknown outputs (SNLSE-UI-UO) and the sub-structure approach are used to identify damages at critical locations (hot spots) of the complex structure. In our approach, only a limited number of response data are needed and the external excitations may not be measured, thus significantly reducing the number of sensors required and the corresponding computational efforts. The accuracy of the proposed approach is illustrated using a long-span truss with finite-element formulation and an 8-story nonlinear base-isolated building. Simulation results demonstrate that the proposed approach is capable of tracking the local structural damages without the global information of the entire structure, and it is suitable for local structural health monitoring.

• 방송공학회논문지
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• 제8권4호
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• pp.392-398
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• 2003

본 논문에서는 MPEG-21 기반 멀티미디어 파일 포맷의 구조, 그리고 파일 내 또는 외부의 동영상, 정지영상, mp4 파일과 같은 미디어리소스를 참조 하는 방법을 통한 파일화 절차를 제안하였다. 제안한 멀티미디어 파일 포맷은 MPEG-4 터미널에서도 상호 운용 가능케 하는 구조(backward compatibility with MPEG-4)이며, XML로 구성된 MPEG-21 콘텐츠인 디지털아이템에서 정의된 미디어리소스를 효과적으로 참조하는 방법을 포함한다. 본 논문에서 정의된 파익 포맷은 디지털 방송, 무선통신, 인터넷 환경에서의 다양한 형태의 콘텐츠들을 효과적이고 체계적으로 조합할 수 있는 기능 및 효과적인 저장 기능을 제공하며, 향후 XML기반 메타데이터와 미디어리소스를 포함하는 멀티미디어 콘텐츠의 파일 포맷에 대한 참고 모델로서 사용될 수 있다.

• Journal of Information Processing Systems
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• 제17권4호
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• pp.834-850
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• 2021

IT security companies have been releasing file system filter driver security solutions based on the whitelist, which are being used by several enterprises in the relevant industries. However, in February 2019, a whitelist vulnerability was discovered in Microsoft Edge browser, which allows malicious code to be executed unknown to users. If a hacker had inserted a program that executed malicious code into the whitelist, it would have resulted in considerable damage. File system filter driver security solutions based on the whitelist are discretionary access control (DAC) models. Hence, the whitelist is vulnerable because it only considers the target subject to be accessed, without taking into account the access rights of the file target object. In this study, we propose an industrial device security system for Windows to address this vulnerability, which improves the security of the security policy by determining not only the access rights of the subject but also those of the object through the application of the mandatory access control (MAC) policy in the Windows industrial operating system. The access control method does not base the security policy on the whitelist; instead, by investigating the setting of the security policy not only for the subject but also the object, we propose a method that provides improved stability, compared to the conventional whitelist method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5765-5781
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• 2018

Extreme learning machine (ELM) is emerging as a powerful machine learning method in a variety of application scenarios due to its promising advantages of high accuracy, fast learning speed and easy of implementation. However, how to select the optimal hidden layer of ELM is still an open question in the ELM community. Basically, the number of hidden layer nodes is a sensitive hyperparameter that significantly affects the performance of ELM. To address this challenging problem, we propose to adopt multiple kernel learning (MKL) to design a multi-hidden-layer-kernel ELM (MHLK-ELM). Specifically, we first integrate kernel functions with random feature mapping of ELM to design a hidden-layer-kernel ELM (HLK-ELM), which serves as the base of MHLK-ELM. Then, we utilize the MKL method to propose two versions of MHLK-ELMs, called sparse and non-sparse MHLK-ELMs. Both two types of MHLK-ELMs can effectively find out the optimal linear combination of multiple HLK-ELMs for different classification and regression problems. Experimental results on seven data sets, among which three data sets are relevant to classification and four ones are relevant to regression, demonstrate that the proposed MHLK-ELM achieves superior performance compared with conventional ELM and basic HLK-ELM.

• International Journal of Computer Science & Network Security
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• 제21권9호
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• pp.31-40
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• 2021

The increasing number of credit card fraud cases has become a considerable problem since the past decades. This phenomenon is due to the expansion of new technologies, including the increased popularity and volume of online banking transactions and e-commerce. In order to address the problem of credit card fraud detection, a rule-based approach has been widely utilized to detect and guard against fraudulent activities. However, it requires huge computational power and high complexity in defining and building the rule base for pattern matching, in order to precisely identifying the fraud patterns. In addition, it does not come with intelligence and ability in predicting or analysing transaction data in looking for new fraud patterns and strategies. As such, Data Mining and Machine Learning algorithms are proposed to overcome the shortcomings in this paper. The aim of this paper is to highlight the important techniques and methodologies that are employed in fraud detection, while at the same time focusing on the existing literature. Methods such as Artificial Neural Networks (ANNs), Support Vector Machines (SVMs), naïve Bayesian, k-Nearest Neighbour (k-NN), Decision Tree and Frequent Pattern Mining algorithms are reviewed and evaluated for their performance in detecting fraudulent transaction.

• Journal of Information Processing Systems
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• 제17권1호
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• pp.63-74
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• 2021

According to the double-phase cluster-head election method (DCE), the final cluster heads (CHs) sometimes are located at the edge of cluster. They have a long distance from the base station (BS). Sensor data is directly transmitted to BS by CHs. This makes some nodes consume much energy for transmitting data and die earlier. To address this problem, energy efficient multi-hop cluster-head election strategy (EEMCE) is proposed in this paper. To avoid taking these nodes far from BS as CH, this strategy first introduces the distance from the sensor nodes to the BS into the tentative CH election. Subsequently, in the same cluster, the energy of tentative CH is compared with those of other nodes, and then the node that has more energy than the tentative CH and being nearest the tentative CH are taken as the final CH. Lastly, if the CH is located at the periphery of the network, the multi-hop method will be employed to reduce the energy that is consumed by CHs. The simulation results suggest that the proposed method exhibits higher energy efficiency, longer stability period and better scalability than other protocols.

• Earthquakes and Structures
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• 제20권3호
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• pp.279-293
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• 2021

Most of the existing seismic codes for RC buildings consider only a scenario earthquake for analysis, often characterized by the response spectrum at the specified location. However, any real earthquake event often involves occurrences of multiple earthquakes within a few hours or days, possessing similar or even higher energy than the first earthquake. This critically impairs the rehabilitation measures thereby resulting in the accumulation of structural damages for subsequent earthquakes after the first earthquake. Also, the existing seismic provisions account for the non-linear response of an RC building frame implicitly by specifying a constant response modification factor (R) in a linear elastic design. However, the 'R' specified does not address the changes in structural configurations of RC moment-resisting frames (RC MRFs) viz., building height, number of bays present, bay width, irregularities arising out of mass and stiffness changes, etc. resulting in changed dynamic characteristics of the structural system. Hence, there is an imperative need to assess the seismic performance under sequential earthquake ground motions, considering the adequacy of code-specified 'R' in the representation of dynamic characteristics of RC buildings. Therefore, the present research is focused on the evaluation of the non-linear response of medium-rise 3D RC MRFs with and without vertical irregularities under bi-directional sequential earthquake ground motions using non-linear dynamic analysis. It is evident from the results that collapse probability increases, and 'R' reduces significantly for various RC MRFs subjected to sequential earthquakes, pronouncing the vulnerability and inadequacy of estimation of design base shear by code-specified 'R' under sequential earthquakes.