Intertemporal Characteristics Research Articles

How do students engage with computer-based assessments: impact of study breaks on intertemporal engagement and pass rates

Study breaks and exam revision weeks are increasingly embedded in learning design under the assumption that students would make use of this time to catch up with their study or prepare for upcoming assessment tasks. However, there remains a paucity of empirical evidence to evaluate to what extent the implementation of study breaks, preparation and exam revision weeks impact students’ engagement and academic performance. By applying learning analytics in a computer-based assessment (CBA) setting, this study investigates how study break weeks and assessment preparation weeks impacted the odds of passing a module using a mixed-effect logistic regression on 123,916 undergraduate students in 205 modules over several semesters from 2015–2017 at the Open University. Furthermore, we investigated the intertemporal characteristics of student engagement during preparation weeks for a final assessment in an Introductory Business course over three semesters. A mixed-effect logistic regression was used to model behavioural engagement of 3385 students on the VLE (i.e. click counts) over three semesters during the assessment preparation weeks. Our findings indicated a positive association between study breaks and the odds of passing a course, while there was no statistically significant effect in relation to the number of assessment preparation and revision weeks. Analysis of behavioural engagement on the VLE suggested that there was a higher proportion of passed students remained active during preparation and exam revision weeks compared to failed students. Compared to the pass group, the fail group also exhibited a stronger pattern of procrastination. This study offers new insights that could help institution management and course designer to evaluate the efficacy of using study breaks and exam preparation weeks to improve student retention.

Evaluating Demand Response Impacts on Capacity Credit of Renewable Distributed Generation in Smart Distribution Systems

Environmental concerns and depletion of traditional energy lead to the booming development of renewable distributed generation (RDG) in the past decade. However, due to intermittent nature of renewable energy sources, to what extent RDG could provide capacity to power systems becomes a critical issue to the utility company when implementing long-term system strategic (generation expansion) planning. On the other hand, in a smart-grid frame, the popularization of different varieties of demand-side resources enables the system to operate at more flexible modes ever before. The potential variability in load demand not only introduces additional dynamics and uncertainties to the system, but could also affect the reliability benefits of RDG. Therefore, in practice, to effectively estimate the reliability value of RDG in power systems, the potential interaction between generation- and demand-side must be properly captured. In this paper, a study to assess the capacity credit (CC) of RDG in a context of distributed generation system is performed with consideration of the impacts of demand response (DR). A compound reliability model for DR is presented, which considers the uncertainties involved in both instant response and follow-on load recovery processes. On this basis, an assessment framework for the CC of RDG based on sequential Monte Carlo simulation is developed by which the inter-temporal characteristics of DR resources can be fully captured. The numerical study is implemented based on the IEEE-38 bus test case. The calculation results demonstrate that the CC of RDG would depend on a variety of factors, including penetration level, responsiveness of load demand and the correlations between RDG and DR availability. Also, it is shown that accounting for the underlying effect of DR is of absolute importance, otherwise the CC of RDG might be estimated erroneously in real practices.

Dynamic Optimal Power Flow for Active Distribution Networks

Active Network Management is a philosophy for the operation of distribution networks with high penetrations of renewable distributed generation. Technologies such as energy storage and flexible demand are now beginning to be included in Active Network Management (ANM) schemes. Optimizing the operation of these schemes requires consideration of inter-temporal linkages as well as network power flow effects. Network effects are included in optimal power flow (OPF) solutions but this only optimizes for a single point in time. Dynamic optimal power flow (DOPF) is an extension of OPF to cover multiple time periods. This paper reviews the generic formulation of DOPF before developing a framework for modeling energy technologies with inter-temporal characteristics in an ANM context. The framework includes the optimization of nonfirm connected generation, principles of access for nonfirm generators, energy storage, and flexible demand. Two objectives based on maximizing export and revenue are developed and a case study is used to illustrate the technique. Results show that DOPF is able to successfully schedule these energy technologies. DOPF schedules energy storage and flexible demand to reduce generator curtailment significantly in the case study. Finally, the role of DOPF in analyzing ANM schemes is discussed with reference to extending the optimization framework to include other technologies and objectives.

SCUC With Hourly Demand Response Considering Intertemporal Load Characteristics

In this paper, the hourly demand response (DR) is incorporated into security-constrained unit commitment (SCUC) for economic and security purposes. SCUC considers fixed and responsive loads. Unlike fixed hourly loads, responsive loads are modeled with their intertemporal characteristics. The responsive loads linked to hourly market prices can be curtailed or shifted to other operating hours. The study results show that DR could shave the peak load, reduce the system operating cost, reduce fuel consumptions and carbon footprints, and reduce the transmission congestion by reshaping the hourly load profile. Numerical simulations in this paper exhibit the effectiveness of the proposed approach.

Outsourcing War: The Evolution of the Private Military Industry after the Cold War

In this paper, we study the evolution of private military corporations (PMCs), which are for-profit organizations that subcontract military field services to sovereign authorities as well as to others. Between Eisenhower’s famous “military-industrial complex” speech in 1961 and the post-9/11 war in Iraq, PMCs were transformed from relatively minor subcontractors to major companies with unique capabilities that made them strategically central to the sovereign military organizations from which they had grown. Throughout this period, PMCs exhibited a “hybrid organizational form” as delineated within organizational economics. Our purpose is grounded theorizing in which we derive insights about the evolution of PMCs as hybrid organizational forms. Our analysis suggests that hybrid forms of organization enable transactions and capability development that are not possible within either markets or hierarchies. Hybrid forms may thus represent a conduit for institutional entrepreneurship and the emergence of new industry structures. Their intertemporal characteristics warrant further theoretical study.

Is there cyclical bias in bank holding company risk ratings?

This paper examines whether bank holding company (BHC) risk ratings are asymmetrically assigned or biased over business cycles from 1986 to 2003. In a model of ratings determination which accounts for bank characteristics, financial market conditions, past supervisory information, and aggregate macro-economic factors, we find that bank exam ratings exhibit inter-temporal characteristics. First, exam ratings exhibit some evidence of examiner bias for several periods analyzed. When the business cycle turns, examiners sometime depart from standards that they set during the previous phases of the cycle. However, this bias is not widespread or systematic. Second, exam ratings exhibit some inertia. Our results suggest that examiners rate on the side of not changing (rather than upgrading or downgrading) an institution’s exam rating. Third, we find robust evidence of a secular trend towards more stringent examination BHC ratings standards over time.

Is there Cyclical Bias in Bank Holding Company Risk Ratings?

Outside monitors provide important information that can help stockholders, creditors, regulators and other stakeholders apply market discipline. In the banking industry, government examiners are an additional outside monitor but with one important difference: bank examination ratings are not public information, and are known only to top bank managers. Still, exam ratings directly influence bank operations and performance because they are used to determine banks' required capital and banks' deposit insurance premiums and, in extreme cases, can constrain banks' investment decisions. Because of banks' special role in the economy, changes in exam ratings can have implications for credit availability and economic growth. Unlike corporate bond ratings - which by design attempt to measure steady state credit worthiness across the business cycle - bank exam ratings are designed to reflect bank safety and soundness at a given point-in-time. Indeed, we find that exam ratings for U.S. banking companies exhibit a much greater volatility, although they are correlated with, bond ratings for U.S. banks. Much of this volatility coincides with the contemporaneous phase of the business cycle. However, in a model that controls for bank characteristics, financial market conditions, past supervisory information, and aggregate macroeconomic factors, we find that bank exam ratings exhibit inter-temporal characteristics. First, exam ratings exhibit some examiner bias - which we define as a significant and persistent deviation of our forecasted changes in upgrades, downgrades and no changes from those actually assigned - for most periods analyzed. When the business cycle turns, examiners often depart from standards that they set during the previous phases of the business cycle. However, this bias is not widespread or systematic. Second, exam ratings exhibit some stickiness. In marginal cases, our results suggest that examiners rate on the side of not changing (rather than upgrading or downgrading) an institution's exam rating. Third, we find strong and robust evidence of a secular trend towards more stringent examination ratings standards over time.

Foreign direct investment in industrial research in the pharmaceutical and electronics industries—results from a survey of multinational firms

This paper examines motives, location characteristics, inter-temporal characteristics and modes of entry for foreign direct investment (FDI) in research and development (R&D). The paper is based on a detailed empirical survey of laboratory sites established by 32 large multinational companies domiciled in 5 countries. Findings indicate that FDI in R&D has risen considerably over the last 40 years and that firms invest in R&D sites abroad in order to augment their knowledge base or in order to exploit it. The former motive leads to establishment of facilities primarily close to universities while the latter type leads to establishment of facilities close to existing manufacturing facilities and markets. The paper also finds that greenfield investments are the dominant mode of entry and that firms establish multiple R&D sites in their home countries before investing in such sites abroad.

Heterogeneous households» intertemporal characteristics and the aggregation problem

Aggregation in exchange markets is studied by imposing restrictions on the distribution of the households» intertemporal characteristics. Approximate bounds for the derivatives of market demand that depend upon specific measure of sensitivity of the distribution of households» intertemporal choices to changes in the real interest rate are provided. This has strong consequences for the prevalence, in the aggregate, of gross substitutability between current and future consumption.

Intertemporal and intergenerational pareto efficiency: An extended theorem

In 1976 Sandler and Smith developed a concept of intertemporal Pareto efficiency and derived optimality conditions for a variety of specifications of the intertemporal characteristics of both public and private goods. This analysis led to the conclusion that any discounting of the benefits of a good that is public across generations (or time) as well as individuals would be Pareto inefficient. In this paper it is argued that such a conclusion is warranted only under an unlikely specification of the intertemporal transformation function.