• 한국태양에너지학회 논문집
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• 제30권2호
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• pp.72-80
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• 2010

The main thrust of this paper is to investigate a practical way of generating the monthly averaged daily horizontal solar radiation in Korea. For estimating the horizontal solar radiation, the clearness index($K_T$) and the clearness number($C_N$) which are required for the use of Liu and Jordan's model and ASHRAE Clear Sky model were derived based on the measured weather data. Third-order polynomials returning $K_T$ and��$C_N$ for a given location were derived as a function of cloud amount, month, date, latitude and longitude. The predicted monthly averaged daily horizontal solar radiation values were compared with those acquired from the established design weather data. The MBE(Mean Bias Error) and RMSE (Root Mean Squares for Error) between the predicted values and the measured data were near zero. It means that the suggested third-order polynomials for $K_T$ and $C_N$ have good applicability to Liu and Jordan's model and ASHRAE Clear Sky model.

• Applied Microscopy
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• 제47권3호
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• pp.110-120
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• 2017

Non-isothermal thermogravimetry (TG) measurements on melt-quenched $Bi_xSe_{100-x}$ specimens (x=0, 2.5, 7.5 at%) were made at a heating rate ${\beta}=10^{\circ}C/min$ in the range $T=35^{\circ}C{\sim}950^{\circ}C$. The as-measured TG curves confirm that $Bi_xSe_{100-x}$ samples were thermally stable with minor loss at $T{\leq}400^{\circ}C$ and mass loss starts to decrease up to $600^{\circ}C$, beyond which trivial mass loss was observed. These TG curves were used to estimate molar (Se/Bi)-ratios of $Bi_xSe_{100-x}$ samples, which were not in accordance with initial composition. Shaping features of conversion curves ${\alpha}(T)-T$ of $Bi_xSe_{100-x}$ samples combined with a reliable flow chart were used to reduce kinetic mechanisms that would have caused their thermal mass loss to few nth-order reaction models of the form $f[{\alpha}(T)]{\propto}[1-{\alpha}(T)]^n$ (n=1/2, 2/3, and 1). The constructed ${\alpha}(T)-T$ and $(d{\alpha}(T)/dT)-T$ curves were analyzed using Coats-Redfern (CR) and Achar-Brindley-Sharp (ABS) kinetic formulas on basis of these model functions, but the linearity of attained plots were good in a limited ${\alpha}(T)-region$. The applicability of CR and ABS methods, with model function of kinetic reaction mechanism R0 (n=0), was notable as they gave best linear fits over much broader ${\alpha}(T)-range$.

• Earthquakes and Structures
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• 제16권3호
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• pp.295-310
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• 2019

This study attempts to develop new simplified approximate formulas to predict the fundamental natural periods of vibration (T) for bearing wall systems engaged with special reinforced concrete shear walls (RCSW) under seismic loads. Commonly, seismic codes suggested empirical formulas established by regression analysis of measured T for buildings during earthquake motions. These formulas depend on structure type, building height, number, height and length of SW, and ratio of SW area to base area of structure. In this study, a parametric investigation is performed for T of 110 selected models of bearing RCSW systems with varying structural height, configuration of horizontal plans including building width, number and width of bays, presence of middle corridors and core SWs. For this purpose, a 3D non-linear response time history (TH) analysis is implemented using ETABS v16.2.1. New formulas to estimate T are anticipated and compared with those obtained from formulas of IBC 2012 and ASCE/SEI 7-10. Moreover, the study examines responses of an arbitrarily two selected test model of 60 m and 80 m in height with presence of SWs having middle corridors. It is observed that the performance of the tested buildings is different through arising of considerable errors when using codes' formulas for estimating T. Accordingly, using the present proposed formulas exhibits more reasonable and safer design compared to codes' formulas. The results showed that equitable enhancement is promising to improve T formulas approaching enhanced and accurate estimation of T with reliable analysis, design, and evaluation of bearing RCSW systems.

• 한국안전학회지
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• 제35권3호
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• pp.86-95
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• 2020

This paper describes the work and the results of the final Probabilistic Safety Assessment (PSA) for the Jordan Research and Training Reactor (JRTR). This final PSA was undertaken to assess the level of safety for the design of a research reactor and to evaluate whether it is probabilistically safe to operate and reliable to use. The scope of the PSA described here is a Level 1 PSA, which addresses the risks associated with core damage. After reviewing the documents and its conceptual design, nine typical initiating events were selected regarding internal events during the normal operation of the reactor. AIMS-PSA (Version 1.2c) was used for the accident quantification, and FTREX was used as the quantification engine. 1.0E-15/yr of the cutoff value was used to deliminate the non-effective Minimal Cut Sets (MCSs) when quantifying the JRTR PSA model. As a result, the final result indicates a point estimate of 2.02E-07/yr for the overall Core Damage Frequency (CDF) attributable to internal initiating events in the core damage state for the JRTR. A Loss of Primary Cooling System Flow (LOPCS) is the dominant contributor to the total CDF by a single initiating event (9.96E-08/yr), and provides 49.4% of the CDF. General Transients (GTRNs) are the second largest contributor, and provide 32.9% (6.65E-08/yr) of the CDF.

• The Journal of Asian Finance, Economics and Business
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• 제7권11호
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• pp.33-43
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• 2020

This study aims to investigate the importance of earnings quality as a determinant of companies' performance. It provides some empirical evidences from an emerging market, specifically from the Jordanian market. This study developed an econometric model for the effect of earnings quality on the companies' performance using empirical evidence. The study employs a panel data analysis method by using a sample of all Jordanian industrial public shareholding companies listed on Amman Stock Exchange (ASE) during 2010-2018. The results reveal that Return on Assets (ROA), Return on Equity (ROE), and Earnings Per Share (EPS) as proxies of company's performance are affected by the earnings quality. This provides the importance of positive earnings quality that eventually influences the companies' performance. The results of this study suggest that the higher control level on the managers' behavior and its outcome will have an effect on earnings quality, and thus the company's performance increases. As well as, high relevance of accounting information will improve earnings quality, and thus earnings quality with the interaction factors of the company's environment work on improving performance. As a conclusion, this study can work as a reference to assist standard setters, security analysts, regulators and other accounting-information users in appraising relation between the earnings quality and companies' performance.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.517-523
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• 2021

Audit quality encompasses the key elements that create an environment that maximizes the likelihood that quality audits are performed consistently. This study aimed to identify the impact of auditing quality on the market value of the manufacturing companies listed on the Amman Stock Exchange (ASE). The analytical method was adopted in this research to extract and collect the necessary data. This study hypothesizes that audit quality leads to an increase in the market value by the offering of high-quality services. The study used the panel data approach to analyze cross-sectional data for 41 industrial companies that included time series data for the period (2019-2019). To test its hypotheses, the study used the fixed-effect model. The study found that the audit quality factors (audit office size, client retention period, auditor's fees, and linking with international audit offices) did not have a significant impact on market value. It found also the positive impact of the audit office size on the market value of the listed companies on the ASE for the period from 2009 to 2019. The study recommended the management of the company realize the importance of contracting with audit offices of large size and good reputation because these offices are more capable of increasing their efficiency, qualifying their employees, and thus be fully prepared for the audit process efficiently and effectively.

• The Journal of Asian Finance, Economics and Business
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• 제8권8호
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• pp.453-463
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• 2021

The current study aims to investigate the relationship between CSRD and firm performance, as an indicator for corporate socially responsible behavior, and corporate market performance of listed companies on the Amman stock exchange (ASE). The study adopts a quantitative methodology and utilizes pooled data sets that was collected following content analysis approach of the annual reports for the period 2014 to 2019. The study sample consists of 42 listed companies. The study ran a multiple regression model in order to capture the relationship between the independent variable CSRD and the dependent variable that is Firm performance which was measured using Tobin's Q. The study also utilized five control variables in order to control the hypothesized relationship between CSRD and Firm Performance. The results indicate a negative but significant relationship between CSRD and corporate market performance measured by Tobin's Q. The results stand against the notion of the business case for CSR, and indicate the opposite position, so, the higher CSRD, the lower will be Tobin's Q. Such results support the notion of the institutional theory, and provide an initial evidence for legitimacy seeking behavior in Jordanian companies. However, the results indicate a lower level of awareness of CSR across investors and market players, which support arguments of the difference in market perceptions towards CSR.

• Structural Engineering and Mechanics
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• 제57권2호
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• pp.265-280
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• 2016

A NLFE model was proposed to investigate the mechanical behavior of short columns, cast using plain or fibrous lightweight aggregate concrete (LWAC), and subjected to elevated temperatures of up to $700^{\circ}C$. The model was validated, before its predictions were extended to study the effect of other variables, not studied experimentally. The three-dimensional NLFE model was developed using ANSYS software and involved rational simulation of thermal mechanical behavior of plain and fibrous LWAC as well as longitudinal and lateral steel reinforcement. The prediction from the NLFE model of columns' mechanical behavior, as represented by the stress-strain diagram and its characteristics, compared well with the experimental results. The predictions of the proposed models, considering wide range of lateral reinforcement ratios, confirmed the behaviors observed experimentally and stipulated the importance of steel confinement in preserving post-heating mechanical properties of plain and fibrous LWAC columns, being subjected to high temperature.

• 한국문헌정보학회지
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• 제8권
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• pp.183-207
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• 1981

Library standards have been the source of considerable controversy, whereas many problems are involved in developing stardard for university library collections. For evaluation purposes, standards should be precise, quantifiable and measurable. In the United States, however, standards for academic libraries are limited to qualitative statements and principles. Quantitative standards, when given, are ususally related to the number of population in the institution being served, or the prescribed quantitative objectives are often arbitrarily formulated by value judgements. The study in this paper attempts to explain the problems involved in developing quantitative standard for academic library collections. Two problems facing in the formulation of the optimal size of collection are identified. One is the theoretically faulty concept of adequacy of collection to meet the situations of diversity of university libraies, and the other is the difficulties in quantification and measurement, along with the lack of concept of adequacy of collection. However, quantification of adequate size of collection is proved to be useful on the pratical level, even though not valid theoretically. ACRL, Clapp/Jordan and Voigt developed formulas or models for setting the optimal size of a library collection for any particular university library. The main purpose of this study is the analysis of the above formulas. ACRL standard was drawn from obervation and analysis of statistcs in leading library collections. In academic field, this judgement appears to have been based on the assumption that a high-grade institution would be apt to have a good library collection. This study criticizes ACRL standard for its failure to include some determinants of measurements, and points out the limitations of the standard. In contrast. Clapp/Jordan developed a formula rather scientifically based upon bibliographical sources. This is similarly empirical but has the advantage of bringing into play the elements which make universities diverse in nature. Both ACRL and Clapp/Jordan formulas share two major defects. (1) the specific subject needs of the collection are not indiacted directly, and (2) percentage rate of growth is an indicator in measuring the potential utility of a collection. Thus both formulas failed to provide a basis for meaningful evaluation. Voigt further developed a model for determining acquisition rates for currently published materials based on bibliographic technique. Voigt model encourages experimentation with different programs and different allocations of input resources, designed to meet the needs of the library's particular population. Standard for university library collections can be formulated in terms of input(traditional indicator), or additionally, in terms of output(cost-effectiveness). Cost effectiveness is expressed as user satisfaction, ability to provide wanted materials within a reasonable time period. Thus simple quantitative method does not cover all the situations of diversity of university library collections, nor measures the effectiveness of collections. Valid standard could not be established without further research.

• Structural Engineering and Mechanics
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• 제30권4호
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• pp.427-444
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• 2008

A mathematical model for the nonlinear dynamics of a rotating beam with flexible root attached to a rotating hub with elastic foundation is developed. The model is developed based on the large planar and flexural deformation theory and the potential energy method to account for axial shortening due to bending deformation. In addition the exact nonlinear curvature is used in the system potential energy. The Lagrangian dynamics and the assumed mode method is used to derive the nonlinear coupled equations of motion hub rotation, beam tip deflection and hub horizontal and vertical displacements. The derived nonlinear model is simulated numerically and the results are presented and discussed for the effect of root flexibility, hub stiffness, torque type, torque period and excitation frequency and amplitude on the dynamic behavior of the rotating beam-hub and on its stability.