• Journal of Computing Science and Engineering
• /
• v.7 no.1
• /
• pp.1-20
• /
• 2013

Over the past generation, data warehousing and online analytical processing (OLAP) applications have become the cornerstone of contemporary decision support environments. Typically, OLAP servers are implemented on top of either proprietary array-based storage engines (MOLAP) or as extensions to conventional relational DBMSs (ROLAP). While MOLAP systems do indeed provide impressive performance on common analytics queries, they tend to have limited scalability. Conversely, ROLAP's table oriented model scales quite nicely, but offers mediocre performance at best relative to the MOLAP systems. In this paper, we describe a storage and indexing framework that aims to provide both MOLAP like performance and ROLAP like scalability by essentially combining some of the best features from both. Based upon a combination of R-trees and bitmap indexes, the storage engine has been integrated with a robust OLAP query engine prototype that is able to fully exploit the efficiency of the proposed storage model. Specifically, it utilizes an OLAP algebra coupled with a domain specific query optimizer, to map user queries directly to the storage and indexing framework. Experimental results demonstrate that not only does the design improve upon more naive approaches, but that it does indeed offer the potential to optimize both query performance and scalability.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.8
• /
• pp.3589-3605
• /
• 2018

In this paper, we investigate an individual channel estimation problem for multiple-input multiple-output (MIMO) two-way amplify-and-forward (AF) relay networks. To avoid self-interference during the estimation of the individual MIMO channels, a novel blind interference cancellation (BIC) approach is proposed based on an orthogonal preceding framework, where a pair of orthogonal precoding matrices is utilized at the source nodes. By designing an optimal decoding scheme, we propose to decompose the bidirectional transmission into a pair of unidirectional transmissions. Unlike most existing approaches, we make the practical assumption that the nonreciprocal MIMO channel and the mutual interference of multiple antennas are both taken into consideration. Under the precoding framework, we employ an orthogonal superimposed training strategy to obtain the individual MIMO channels. However, the AF strategy causes the noise at the terminal to be the sum of the local noise and the relay-propagated noise. To remove the relay-propagated noise during the estimation of the second-hop channel, a partial noise-nulling method is designed. We also derive a closed-form expression for the total mean square error (MSE) of the MIMO channel from which we compute the optimal power allocation. The simulation results demonstrate that the analytical and simulated curves match fully.

• Journal of Digital Convergence
• /
• v.7 no.1
• /
• pp.31-47
• /
• 2009

The rapid growth of information and communication technologies prompted the need for developing the strategic implementation framework of IT/ICT programs in universities. Here, we propose a strategic framework for the development of the IT/ICT programs in the universities of the province of Mazandaran in Iran. We use the SWOT analysis to assist the formulation of the strategy, where the Analytic Hierarchy Process (AHP) is applied to weigh the SWOT factors and the fuzzy TOPSIS is used to evaluate the strategic plans. Based on Iran and Mazandaran Digital Indices (DI) and considering the SWOT matrix, four strategies are identified. Finally, an analytical concept, namely the strategy shooting, is considered to show the role of SWOT factors and strategic plans on the performance of the system.

• Journal of Communications and Networks
• /
• v.17 no.6
• /
• pp.634-646
• /
• 2015

Assuming perfect channel state information (CSI) at the transmitter and receiver, the optimization problem of maximizing the minimum Euclidean distance between two received signals by a linear precoder is considered for multiple-input multiple-output (MIMO) systems with arbitrary dimensions and arbitraryary quadrature amplitude modulation (QAM) input. A general precoding framework is first presented based on the Gram matrix, which is shown for 2-dimensional (2-D) and 3-dimensional (3-D) MIMO systems when employing the ellipse expanding method (EEM). An extended precoder for high-dimensional MIMO system is proposed following the precoding framework, where the Gram matrix for high-dimensional precoding matrix can be generated through those chosen from 2-D and 3-D results in association with a permutation matrix. A complexity-reduced maximum likelihood detector is also obtained according to the special structure of the proposed precoder. The analytical and numerical results indicate that the proposed precoder outperforms the other precoding schemes in terms of both minimum distance and bit error rate (BER).

• Journal of the Korea Safety Management & Science
• /
• v.9 no.2
• /
• pp.195-214
• /
• 2007

The purpose of this study is to explore the applicability of AHP(Analytic Hierarchy Process) to select more productive projects among various proposed projects in a particular company. To achieve this research objective, the characteristics of project evaluation and selection are first reviewed with respect to when, where, and how the decision is made. Then the theoretical basis of the AHP is briefly reviewed along with its mathematical underpinnings to construct the framework of project evaluation and selection. To be more specific, the evaluation and selection criteria were reorganized in the AHP-based framework to make the process of project evaluation and selection more productive. Project evaluation and selection is one of the most important activities for the most companies to be more advantageous in the market. Despite the importance of decision making process of project selection, not many of how to choose the best project were suggested as the reliable project selection methods in the industries. It may be because it involves various activities related to conflict resolution among different evaluation criteria, high uncertainties of market, and the unclear tradeoff among various project objectives. Furthermore, the decision, once made at this point, tends to be irrevocable until the whole process turns out to be a complete success or failure. As the result, the AHP method showed better financial performance rather than the traditional method in a case study.

• The Journal of Asian Finance, Economics and Business
• /
• v.6 no.1
• /
• pp.91-105
• /
• 2019

The paper aims to combine balance sheet analysis at the firm level with the International Monetary Fund's public debt sustainability assessment framework to assess state-owned enterprises' (SOE) leverage as a contingent liability to the public sector. Based on company data and the interest coverage ratio as a measure of debt at risk, aggregate baseline scenarios are projected to gauge the magnitude of SOE debt as a contingency. SOE's financial and debt ratios are first bootstrapped to generate firm-level distributions and then averaged into a fan chart of the economy-wide SOE contingent liability. Applied to the People's Republic of China as an example, the study finds that by the end of 2015 SOE leverage had grown to a substantial liability. However arbitrary the assumptions underlying these projections, it would appear that even if authorities had to mop up as much as 20% of SOE debt at risk gone bad, this would have been manageable at roughly 2.7% of the gross domestic product in 2016 or 5.5% by 2021. This projection framework is fully amenable to alternative assumptions and settings, which makes it a useful analytical tool to monitor contingent liabilities from non-financial corporate debt that have been building in emerging and advanced economies alike.

• International journal of steel structures
• /
• v.18 no.4
• /
• pp.1177-1190
• /
• 2018

This study presents an analytical framework for estimating the thermo-mechanical behavior of a composite beam exposed to fire. The framework involves: a fire simulation from which the evolution of temperature on the structure surface is obtained; data transfer by an interface model, whereby the surface temperature is assigned to the finite element model of the structure for thermo-mechanical analysis; and nonlinear thermo-mechanical analysis for predicting the structural response under high temperatures. We use a plastic-damage model for calculating the response of concrete slabs, and propose a method to determine the stiffness degradation parameter of the plastic-damage model by a nonlinear regression of concrete cylinder test data. To validate simulation results, structural fire experiments have been performed on a real-scale steel-concrete composite beam using the fire load prescribed by ASTM E119 standard fire curve. The calculated evolution of deflection at the center of the beam shows good agreement with experimental results. The local test results as well as the effective plastic strain distribution and section rotation of the composite beam at elevated temperatures are also investigated.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.45 no.1
• /
• pp.73-93
• /
• 2021

This study typifies fashion mobile plays in a digital environment and explores the experiential value created by them through a case study of a fashion brand mobile app. For the case analysis, mobile plays were divided into four types: intrinsic motivation/active participation, intrinsic motivation/passive participation, external motivation/active participation, and external motivation/passive participation, depending on the mobile players motivation and level of participation. Among the global fashion brand mobile apps released from 2009 to 2019, 16 cases suitable for the analytical framework were used for final analyses. The main results are as follows. First, mobile play value include characteristics such as networkability, immersion, hyper-spatiality, and super-temporality in addition to the attributes of a traditional play such as spontaneity, uncertainty, regularity, and playfulness. Second, the four types of mobile play provide participants with an experiential value such as creative value, emotional value, social value, and exploitative value. This study has academic implications in terms of introducing a new framework that can typify mobile plays and suggest practical implications for what experiential value fashion companies can give consumers through mobile app marketing.

• Geomechanics and Engineering
• /
• v.15 no.5
• /
• pp.1071-1080
• /
• 2018

The study of behavior and values of deformations in the geological medium makes the scientific basis of the methodology of synthesis of true values of parameters of its physico-mechanical and density properties taking into account the influence of geodynamic impacts. The segments of continuous variation of homogeneous elastic uniform deformations are determined under overall compression of the medium. The limits of these segments are defined according to the criteria of instability (on geometric form changes and on "internal" instability). Analytical formulae are obtained to calculate current and limiting (critical) values of deformations within the framework of various variants of small and large initial deformations of the non-classically linearized approach of non-linear elastodynamics. The distribution of deformation becomes non-uniform in the medium while the limiting values of deformations are achieved. The proposed analytical formulae are applicable only within homogeneous distribution of deformations. Numerical experiments are carried out for various elastic potentials. It is found that various forms of instability can precede phase transitions and destruction. The influence of these deformation phenomena should be removed while the physico-mechanical and density parameters of the deformed media are determined. In particular, it is necessary to use the formulae proposed in this paper for this purpose.

• Korean Institute of Interior Design Journal
• /
• v.19 no.2
• /
• pp.117-125
• /
• 2010

Theories and concepts emerging in new media environment are influencing the field of current spatial design. Art and technology have always coexisted, not but they are differentiated in two parts. They show new communicational paradigm in terms of supplementary position each other. The fact that examining the expression method and the communicational structure of today's new media art will be an analytical tool which analyzes the concepts of contemporary spatial design. For this, we attempt to use the Bolter and Gusin's remediation theory as analytical tool. First of all, we consider its theoretical aspects, and then, classify them according to the creation method, and investigate the characteristics of expression according to their types. We prepared an framework of analysis using the Remediation theory and its traits. We reviewed the relations between new media and spaces concerning remediation. After researching, we could analyze the cognitive aspects between new media and spaces as immediacy, and recognize the operational aspects of visual image as hypermediacy. Through the analysis, we could recognize the traits that digital environmental simulacres, sense of telepresence, and non-linear hypermediacy etc. remediate with repeating of mediation of mediation.