Load frequency control (LFC) of modern power systems tends to employ open communication networks to transmit measurement/control signals. Under a limited network bandwidth, the continuous and ...high-sampling-rate signal transmission will be prone to degradation of the LFC performance through network congestion. This brief proposes a decentralized control performance standards (CPSs)-oriented event-triggered (ET) LFC scheme for power systems under constrained communication bandwidth. The proposed scheme comprises the ET LFC scheme and the CPSs-oriented regulation scheme. In the CPSs-oriented regulation scheme, regulation rules are designed to adjust the threshold parameter of the ET LFC scheme based on the North American Electrical Reliability Council (NERC)'s CPS1 and CPS2. The rules generate a larger threshold parameter to lower the triggering frequency in order to reduce unnecessary transmission of measurement/control signals, while ensuring the frequency and tie-lie power of the power systems to meet the required CPS1 and CPS2 instead of the asymptotic stability requirement in the existing research. The reduced transmission of these signals lessens the communication burden. In addition, the decentralized control strategy is used to solve the problems of poor large scalability and computational dimension caused by the centralized control strategy. The effectiveness of the proposed scheme is evaluated on an IEEE 39-bus test system with renewable energy sources.
The objective of this study is to evaluate the factorial structure of the Spanish version of the Individual Work Performance Questionnaire (Version 1.0) and to estimate the impact that acquiescence ...has on it as response bias. Exactly 500 workers from organizations from different industries, primarily located in Ecuador, participated in this study. The comparison of different models using Confirmatory Factor Analysis proved that when acquiescence is not controlled, evidence leads to the rejection of a one-dimensional-or essentially one-dimensional-structure (bifactor model), thus questioning the initial conceptualization of the construct. But when this response bias is controlled, both the one-dimensional model (X.sup.2 = 429.608 223, p < .001; CFI = .974; TLI = .982; RMSEA = .043; SRMR = .063) and the bifactor model (X.sup.2 = 270.730 205, p = .001; CFI = .992; TLI = .994; RMSEA = .026; SRMR = .047) show relevant improvement in terms of goodness of fit over the three-correlated-factors model (X.sup.2 = 537.038 132, p < .001; CFI = .950; TLI = .942; RMSEA = .079; SRMR = .070). However, the low reliability of the substantive factors of the bifactor model makes the one-dimensional model preferable in applied studies. Finally, the results show how mistakes could be made when concluding on the possible relationships between work performance and other relevant variables, in case acquiescence is not controlled.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Most studies report a positive relationship of work engagement with health and job performance, but, occasionally, a "dark side of engagement" has also been uncovered. The current study examined two ...hypotheses: whether work engagement has (1) a U-shaped curvilinear relation with psychological distress and (2) an inverted U-shaped curvilinear relation with job performance (i.e., in-role performance and creative behavior). A two-wave longitudinal Internet survey with a time lag of seven months was conducted among 1,967 Japanese employees. To test our hypotheses, we used a two-wave panel design and examined the lagged and concurrent relations between work engagement and both outcomes. The results confirmed that work engagement had a curvilinear relation with psychological distress concurrently; a favorable effect was found initially, but this disappeared at intermediate levels of work engagement, and, at higher levels, an adverse effect became prominent. In addition, work engagement had a curvilinear relation with in-role performance both concurrently and longitudinally; the higher the levels of work engagement, the stronger the favorable effects on in-role performance. However, contrary to our expectations, work engagement had a linear relation with psychological distress longitudinally and with creative behavior both concurrently and longitudinally. Hence, our results suggest that work engagement plays a different role in health enhancement compared to performance enhancement. Leveling-off and adverse effects of high work engagement were observed for psychological distress in the short and not in a long run. In contrast, no leveling-off effect of high work engagement was observed for job performance. Thus, except for the short-term effect on psychological distress, no dark side of work engagement was observed for psychological distress and job performance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Integrating Performance Management and Enterprise Risk Management Systemsoffers a novel understanding of the multifaceted shades that surround the long called-for and yet not realised integration ...between performance management and enterprise risk management systems.
The residential sector is the third largest electricity user in Taiwan. A clear understanding of the rapid growth in its electricity consumption is crucial to the formulation of policy. This study ...applied the Logarithmic Mean Divisia Index (LMDI) to a decomposition of Taiwan’s residential electricity consumption based on eighteen electrical appliances. Data was obtained from questionnaire surveys conducted in 7677 households. Note that this study was conducted at various disaggregation levels in order to characterize the consumption of electricity in terms of the factors that contribute to specific end-uses.
Climate was identified as the primary factor driving growth in the residential electricity consumption, accounting for an increase of 2.03 billion kWh between 2014 and 2017. In Taiwan, climatic effects manifest primarily as a substantial increase in the use of air-conditioners for cooling. Thus, efforts should be made to accelerate the replacement of low energy-efficiency air conditioners. The same methods could also be used to promote energy upgrades in existing buildings. Our analysis of specific end-uses revealed that the inefficiency of personal computers and dehumidifiers is an important factor in residential electricity consumption. Thus, minimum energy performance standards (MEPS) should be expanded to include these appliances.
•This study identified factors influencing electricity consumption in the residential sector.•The electricity consumption for specific end-uses is decomposed into corresponding factors.•Contribution from climate effect is investigated by considering cooling degree days.•Four policy implications are proposed by analyzing the driving factors in depth.
Evidence from more than 100 y of research indicates that conscientiousness (C) is the most potent noncognitive construct for occupational performance. However, questions remain about the magnitudes ...of its effect sizes across occupational variables, its defining characteristics and functions in occupational settings, and potential moderators of its performance relation. Drawing on 92 unique meta-analyses reporting effects for 175 distinct variables, which represent n > 1.1 million participants across k > 2,500 studies, we present the most comprehensive, quantitative review and synthesis of the occupational effects of C available in the literature. Results show C has effects in a desirable direction for 98%of variables and a grand mean of ρ̄M = 0.20 (SD = 0.13), indicative of a potent, pervasive influence across occupational variables. Using the top 33% of effect sizes ( ρ̄ ≥ 0.24), we synthesize 10 characteristic themes of C’s occupational functioning: 1) motivation for goal directed performance, 2) preference for more predictable environments, 3) interpersonal responsibility for shared goals, 4) commitment, 5) perseverance, 6) self-regulatory restraint to avoid counterproductivity, and 7) proficient performance—especially for 8) conventional goals, 9) requiring persistence. Finally, we examine C’s relation to performance across 8 occupations. Results indicate that occupational complexity moderates this relation. That is, 10) high occupational complexity versus low-to-moderate occupational complexity attenuates the performance effect of C. Altogether, results suggest that goaldirected performance is fundamental to C and that motivational engagement, behavioral restraint, and environmental predictability influence its optimal occupational expression. We conclude by discussing applied and policy implications of our findings.
In most countries, minimum energy performance standards (MEPS) and energy labels are the key policies to accelerate the diffusion of energy-efficient appliances and to help meet energy efficiency and ...climate policy targets. This paper estimates country-specific multivariate econometric models for eight EU countries over the period of 2007–2017 to evaluate the combined effects of changes in the MEPS and the energy labels entering into force in the EU in 2010 and 2011. The findings suggest that these policies increased the market share of cold appliances (refrigerators and fridge-freezer combinations) with an energy label of A+ and better between about 15 and 38 percentage points. For these appliances, autonomous developments (captured through a time trend) are estimated to range between 5 and 10 percentage points per year. Thus, failure to account for autonomous developments would have resulted in substantially overestimating the combined effects of MEPS and energy label policies in the EU. The findings further imply that policy evaluations should allow for policy effectiveness and autonomous developments to differ across countries.
•Evaluation of changes in 2010/2011 EU MEPS and energy labels for cold appliances.•Econometric analyses for market shares in 8 EU countries accounting for counterfactual.•MEPS and labels increased market share of A+ and better between ca. 15 and 38 -% points.•Autonomous effects account for about 5–10 -% points.
Drawing on the ability-motivation-opportunity model, this meta-analysis examined the effects of three dimensions of HR systems—skills-enhancing, motivation-enhancing, and opportunity-enhancing—on ...proximal organizational outcomes (human capital and motivation) and distal organizational outcomes (voluntary turnover, operational outcomes, and financial outcomes). The results indicate that skill-enhancing practices were more positively related to human capital and less positively related to employee motivation than motivation-enhancing practices and opportunity-enhancing practices. Moreover, the three dimensions of HR systems were related to financial outcomes both directly and indirectly by influencing human capital and employee motivation as well as voluntary turnover and operational outcomes in sequence.
The association of irregular sleep schedules with circadian timing and academic performance has not been systematically examined. We studied 61 undergraduates for 30 days using sleep diaries, and ...quantified sleep regularity using a novel metric, the sleep regularity index (SRI). In the most and least regular quintiles, circadian phase and light exposure were assessed using salivary dim-light melatonin onset (DLMO) and wrist-worn photometry, respectively. DLMO occurred later (00:08 ± 1:54 vs. 21:32 ± 1:48; p < 0.003); the daily sleep propensity rhythm peaked later (06:33 ± 0:19 vs. 04:45 ± 0:11; p < 0.005); and light rhythms had lower amplitude (102 ± 19 lux vs. 179 ± 29 lux; p < 0.005) in Irregular compared to Regular sleepers. A mathematical model of the circadian pacemaker and its response to light was used to demonstrate that Irregular vs. Regular group differences in circadian timing were likely primarily due to their different patterns of light exposure. A positive correlation (r = 0.37; p < 0.004) between academic performance and SRI was observed. These findings show that irregular sleep and light exposure patterns in college students are associated with delayed circadian rhythms and lower academic performance. Moreover, the modeling results reveal that light-based interventions may be therapeutically effective in improving sleep regularity in this population.
Recently, electric power consumption has increased rapidly owing to the development of electric devices, and thus environmental problems such as global warming have come to the fore. Therefore, ...developed and developing countries are preparing various measures to prevent global warming. Minimum energy performance standards (MEPS) are one of the representative measures. MEPS is an efficiency regulation for induction motors that limits the minimum efficiency with regard to the power of the induction motors, in order to save energy. Studies have been conducted on induction motors to improve the efficiency and to satisfy MEPS. However, It is very difficult to satisfy the efficiency of induction motor for MEPS. Therefore, synchronous reluctance motors (SynRMs) are actively being studied to replace induction motors. In this paper, a SynRM is designed using a Kw-map. Moreover, to improve the output characteristics, the rib thickness of the SynRM is optimized using the response surface method. Finally, the validity of the design method, proposed in this paper is verified with a real test using the prototype.
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