Multi-period Analysis Research Articles

Optimal attention allocation: picking alpha or betting on beta?

We investigate a problem of attention allocation and portfolio selection with information capacity constraint and return predictability in a multi-asset framework. In a two-phase formulation, the optimal attention strategy maximizes the combined expected alpha payoffs and expected beta payoffs of the portfolio. Return predictors taking extreme values incentivize the investor to learn about them and this leads to competition among information sources for attention. Moreover, the investor trades with varying skills including picking alphas and betting on beta, depending on the magnitude of the related predictors. Our multi-period analysis using reinforcement learning demonstrates time-horizon effects on attention and investment strategies.

An economic-environmental energy management system design for MT-HVDC networks via a semi-definite programming approximation with robust analysis

This research deals with the economic-environmental dispatch problem (EEDP) in multi-terminal high-voltage direct-current (MT-HVDC) systems by proposing a convex approximation based on semi-definite programming (SDP). The exact formulation of the EEDP corresponds to a non-convex, nonlinear programming problem due to the presence of a nonlinear quadratic constraint regarding the products between voltage variables. The thermal plants' economic and objective functions are modeled using typical quadratic functions. The SDP approach allows reaching a convex approximation that ensures the global optimal solution for each objective function independently or the construction of the optimal Pareto front via the weighting-factor optimization methodology. The proposed SDP approach also considers uncertainties in the demand and in the available power of renewable sources, which makes it robust. The main contribution of this research is a multi-period analysis that includes large-scale renewable generation sources and a robust analysis regarding demand and variations in renewable generation. Numerical results in two MT-HVDC systems demonstrate the effectiveness of the proposed SDP approach when compared to combinatorial optimization algorithms. All numerical simulations were carried out using the CVX convex disciplined tool, with the help of the SEDUMI and SDPT solvers, in the MATLAB programming environment.

Impact of the COVID-19 Pandemic on United States' Hotel Productivity: A Multi-Period Analysis

Impact of the COVID-19 Pandemic on United States' Hotel Productivity: A Multi-Period Analysis

Assessing radiometric calibration methods for multispectral UAV imagery and the influence of illumination, flight altitude and flight time on reflectance, vegetation index and inversion of winter wheat AGB and LAI

Radiometric correction is essential to unmanned aerial vehicle (UAV) precision agriculture applications, especially for crop multi-period analysis and quantitative inversion of phenotypic and physiological parameters. In this study, we investigated the performance of four radiometric correction methods: “Camera only” (A), “Camera and sun irradiance” (B) and “Camera, sun irradiance and sun angle” (C) methods provided by Pix4d Mapper and an irradiance sensor-based method (D) implemented with the R software. UAV campaigns were conducted at flight altitudes of 30 m, 60 m and 90 m under clear and cloudy skies at different times over an experimental field of winter wheat. The influences of illumination, flight altitude and flight time on reflectance and vegetation indexes derived from different radiometric calibration methods were analyzed. Moreover, we further assessed the impact of reflectance and vegetation index variations on the above-ground biomass (AGB) and leaf area index (LAI) estimations of winter wheat. Results showed that method D is a promising approach for radiometric calibration, which produced consistent reflectance with method A at noon (e.g., 10:44:41 AM March 17 and 11:39:37 AM April 7) and mid-afternoon (e.g., 15:30:02 PM May 1) and more reliable reflectance in the morning (e.g., 7:15:44 AM March 17). Methods B and C seriously underestimated the reflectance at 10:44:41 AM March 17 and 11:39:37 AM April 7. This was caused by the incorrect attitude angles of the irradiance sensor and further miscalculation of the solar irradiance by Pix4d Mapper. Interestingly, these errors were eliminated in the calculation of the ratio type of vegetation indexes. Methods B and C yielded vegetation indexes that were almost the same as those of methods A and D. Under cloudy sky, when direct sunlight is not blocked by clouds, method D was effective; with cloud occlusion, results on April 24 indicated that the method failed to estimate the total sunlight and direct sunlight ratio. Reflectance and vegetation indexes obtained from different radiometric correction methods were all obviously affected by flight altitude. Furthermore, the variations of NDVI with flight altitude increasing were different with reflectance. Changes in reflectance and vegetation indexes with flight altitude had little effect on the correlation coefficients yielded with AGB, but showed a significant influence on those of LAI. Through analyzing the variation of observed solar radiation at different time intervals, caution is recommended when using the assumption that solar radiation is stable during the UAV flight. The longer the flight, the greater the variation in solar radiation, especially at sunrise and sunset. Even at noon, when the flight duration is 30 min, the change in solar radiation may exceed 10 % (e.g., 16.5 % on March 20).

PERCEIVED WORKPLACE AGEISM AND OLDER WORKERS’ LABOR FORCE TRANSITIONS DURING THE GREAT RECESSION

Abstract Previous research suggests that workplace ageism increased during the Great Recession (GR). During the GR, despite having lower unemployment rates compared to younger workers, older workers took considerably longer to find jobs once they were unemployed. Yet, no study has investigated the potential role of workplace ageism in older workers’ labor force outcomes. This study examines the role of perceived workplace ageism in older workers’ labor force transitions during the GR using longitudinal data from the Health and Retirement study. I conduct a multi-period analysis and compare how the association of perceived workplace ageism with labor force transitions changed during the GR compared to pre and post-recession periods. Results from multivariate logistic regressions show that only in the GR period, both measures of perceived workplace ageism – pressure to retire before age 65 and preference for young in promotions – were associated with a higher likelihood of employment instability (b= 0.336 p< 0.05 and b= 0.340 p< 0.05), net of demographic, socioeconomic, financial, job-related and health-related factors. Moreover, older workers perceiving workplace were less likely to retire and thereby more likely to be unemployed (b= -0.667 p< 0.05). In contrast, perceived workplace ageism had no association with reducing or increasing the hours worked per week. In sum, this study provided the first individual-level evidence on the impact of perceived workplace ageism on older adults’ labor force transitions during the GR. Findings can be used to motivate additional studies on older workers’ experience during the Covid19 crisis.

A multi-period analysis of a water management arena in the Italian Alps, circa 1951–2007: The territorialisation of environmental concerns

Water exploitation is at the centre of current social and environmental sustainability discourses, one form of which is hydropower. Intense damming of rivers and natural basins occurred in nineteenth and twentieth century Europe (and elsewhere). Following Miller and Power's concept of territorialisation and Foucault's notion of visibility, this study sheds light on the water management arena, read through changes in stakeholder objectives and accountabilities. Its focus is on the ‘accounts’ of environmental concerns, from post WWII to the new millennium. The analysis focuses on the case of the Santa Giustina dam in Northern Italy, using archival and oral-history approaches. It is shown how an increasing visibility of environmental concerns translated into a higher degree of ‘territorialisation’ through their itemisation in water quality and quantity parameters. This historical evolution informs policy makers, managers and society in general, about how to address profits and environmental issues regarding current water exploitation.

Multi-period Analysis and Household Registration Differences of Multidimensional Poverty Among Migrant Workers

Multi-period Analysis and Household Registration Differences of Multidimensional Poverty Among Migrant Workers

Low-Carbon Energy Transition for the Sarawak Region via Multi-Period Carbon Emission Pinch Analysis

The Paris agreement in 2015 has required that countries commit to global carbon emission reduction by setting their national targets. In most countries, the electricity sector is identified as one of the major contributors to carbon emissions. Therefore, the governments count on decarbonizing the electricity sector to achieve their carbon reduction targets. However, this could be challenging as it is complex and involves multi-stakeholders in implementing the decarbonization plan. This work presents a mathematical optimization model to determine multi-period electricity generation planning to achieve the electricity demand and the carbon reduction target. A multi-period analysis allows long-term planning for decarbonizing the electricity sector by the gradual phasing out of coal-based power plants and the introduction of renewable-based electricity generation. To illustrate the proposed approach, the developed model is solved to strategize low-carbon energy transition planning for the Sarawak region in Malaysia. The model determines the optimal amount of new renewables required during each of the time periods, from 2020–2040, to meet the carbon reduction target. The optimal results are generated under two scenarios—no co-firing and co-firing. The generated results show that the co-firing scenario resulted in a 14.09% reduction in new renewable additions and a 5.78% reduction in the total costs. The results also determined a 66% reduction in coal consumption in 2050 when compared to the base year in 2020.

Impact of Chinese Capital Outflows on Bitcoin vs. Yuan Relationships: A Multi-Period Analysis

We examine the relationships among Bitcoin (BTC), the Chinese Yuan (CNY), and Chinese capital outflows between 2014-2021. We find that BTC returns strongly comove with CNY returns after 2018Q1, while no significant BTC/CNY relationship exists before 2018Q1. Further, the strength of the BTC/CNY relationship increases throughout 2018 to the present date. Yet, this relationship strength cannot be explained by periods of ascending BTC prices, changes in crypto mining location, nor changes in the use of BTC "mining pools". Instead, we find that the strength of the BTC/CNY relationship is strongly and directly related to Chinese capital outflows. We find no similar relationship with a "bogey" currency, the Euro, implying that the capital outflows -to- BTC/CNY relationship is unique to China and its capital outflow environment. In total, our novel results suggest that BTC is used as part of a process to move economically significant amounts of capital from mainland China.

Is European Green Deal Doomed to Share the Paths of Previous Multiannual EU Strategies?

Goal – to analyse feasibility of the European Green Deal in the perspective of implementation experience of the previous multiannual EU strategies. Research methodology – comparative multi-level and multi-period analysis, review of documentation and literature review and other methods including synthesis and deduction. Score/results – the authors indicated a number of problems hindering the implementation of past multiannual EU strategies that were not solved in the current one. However, potential success factors of the European Green Deal implementation were also identified. Originality/value – value of the analysis lays in contextual reference to development and growth programmes of the EU. Conclusions are based on the comparative approach. The paper is original, not previously published.

A multidimensional and multi-period analysis of safety on roads

This paper proposes a multidimensional and multi-period analysis of safety on roads. It aggregates different road safety performance indicators observed over different periods for which multicriteria and multi-period approaches are used. The criticality of a road depends on the interaction of various factors, such as human factors, causes of accidents and their severity levels, and the characteristics/states of the roads. Therefore, there is a need for a multidimensional view of risk and its consequences concerning traffic accidents. Furthermore, using the Multiple Criteria Decision Making/Aid methods (MCDM/A) allows the performance of roads in the multiple criteria to be considered according to the decision maker's preferences. On the other hand, the temporal approach reflects the performance of roads and their accidents in different periods, enabling the information on the temporal behavior of accidents to be aggregated to the result. Given that Brazil has a vast road network, there is thus the problem of prioritizing road segments to allocate resources for traffic accident prevention and mitigation actions, especially as these resources are usually limited and scarce. For that, a case study is developed in the state of Pernambuco in Brazil. Eleven road segments are analyzed. The strategic objective of the decision-maker is to have a broader view, initially, of the criticality of these road segments in terms of safety so that strategically he can allocate resources to prevent and mitigate the risks of traffic accidents. For this, the decision-maker considered eleven criteria. These represent the different dimensions that can influence traffic accidents, such as the damage (impacts) to human beings or other consequences resulting from traffic accidents and issues related to the characteristics/state of the road and its traffic. Five periods of time were considered to incorporate the temporal influence of these dimensions (2015 to 2019). As a result, it is seen that, for a more comprehensive assessment, it is essential to consider a multidimensional view of risk and a multi-period evaluation, thus incorporating more information into the decision model and thereby making its results more assertive.

نماذج المحاكاة- محاكاة مونتي كارلو- كأسلوب كمي من أساليب النمذجة واتخاذ القرارات - مقاربة نظرية وتطبيقية

Our research aims to try to present the modeling mechanisms in the field of simulation and quantitative methods. The research is a presentation of the role of quantitative methods in making investment project evaluation decisions, more than that and is the use of the Monte Carlo simulation model in evaluation and multi-period analysis of investment projects under conditions Risk and uncertainty. And highlighting the theoretical, scientific and practical importance of the Monte Carlo simulation method in particular, and the importance of using quantitative methods in helping to make decisions in general

A multi-period analysis of the integrated item-sharing and crowdshipping problem

The integrated item-sharing and crowdshipping problem arises from the operational planning of sharing platforms that coordinate diverse services offered by individuals to peers. Item-sharing means to rent-out items whereas crowdshipping describes the willingness of private drivers to conduct deliveries on their planned trips. Integrating both concepts on a single platform can lead to higher profits and better service quality by transferring items through crowdshippers. We investigate a multi-period variant of the problem to facilitate more foresighted assignments of items to requests and crowdshippers. Thereby, items can be used to sequentially serve multiple requests without being returned to their initial locations. This so-called ’request chaining’ cuts transportation effort and improves the availability of items to customers. From a modeling perspective, the planning problem is an example for the rarely investigated many-to-many pickup and delivery problems. We present a binary program and we address problem inherent dynamics due to new incoming announcements by both deterministic and stochastic problem solving approaches that are based on a rolling horizon framework. Furthermore, a simulation environment is set up to investigate the effect of a responsive requesting behavior due to word-of-mouth. Our experiments show that some look-ahead in the planning is particularly useful for scenarios with few requests. The consideration of stochastic information can improve operational performance and word-of-mouth can best be dealt with when consumers interact locally. We also derive managerial insights on the number of items that should be provided in such a community, subject to consumer preferences.

Debottlenecking of biomass element deficiency in a multiperiod supply chain system via element targeting approach

The global trend is moving towards practising sustainability. Various renewable resources have been discovered and promoted to substitute non-renewable consumables. Biomass is identified to be one promising renewable resource for value-added products and bioenergy generation. Despite the promising potential of biomass utilisation, biomass processors are facing challenges to secure constant supply of raw material due to the seasonal and fluctuation availability of biomass. In this work, a biomass supply chain model considering fluctuation availability is studied and optimised using element targeting approach and multiperiod analysis. The conceptual case study proposes optimal biomass storage strategy across multiperiod of interest and highlights supply chain debottlenecking strategy by looking into biomass element deficiency within a technology's element acceptance range. The application of element targeting approach in biomass supply chain optimisation improves process feed selection and biomass utilisation from local resources.

Do tweets create value? A multi-period analysis of Twitter use and content of tweets for manufacturing firms

In this research we enquire if adoption of Twitter by manufacturing firms creates any value for the firm. We conduct two studies to examine the relationship between Twitter related activities of manufacturing firms and the market reaction towards these firms. We collect a novel multi-period dataset and analyse the overall impact of adoption of Twitter on Tobin's Q by employing a propensity score matching and difference-in-difference research design. Our findings suggest that adoption of Twitter increases the value of the firm post adoption. We also conduct additional robustness check such as use of Industry Week data as a proxy of firm value and find our results to be consistent. We adopt a text mining-based approach and examine the communication environment of the manufacturing firms. We use the Latent Dirichlet Allocation (LDA) algorithm for short texts and identify six broad topics among tweets posted by firms. Our panel regression based analysis suggests that there is positive association between divulging product related information and Tobin's Q. Our research showcases the strong impact of use of Twitter and contributes to the nascent literature on firm generated content. It is likely to encourage managers of manufacturing firms to start actively using Twitter for sharing product related information on social media.

The standard market risk model of the Swiss solvency test: an analytic solution

The full standard model of the Swiss solvency test (SST) requires a Monte Carlo simulation to calculate the regulatory target capital. This paper derives an alternative fast Fourier transform-based computational approach for calculating the target capital of the SST that is more than 600 times faster than a Monte Carlo simulation. We also show that the relative computational error of our approach is much smaller than that of the saddlepoint approximation method: the error of the former is less than 10-8, whereas the error of the latter can be as large as 24% for the numerical examples we consider. Our algorithm is relevant for applications requiring both speed and precision, such as multiperiod SST analysis, portfolio optimization and, more generally, the various economic asset and liability management applications of non-Swiss insurers, for which the expected shortfall of asset and liability fluctuations needs to be calculated in a fast and accurate way.

Stakeholder Participation in the Development of International Public Sector Accounting Standards (IPSAS): A Multi-Issue and Multi-Period Analysis of the Due Process

This article analyses the International Public Sector Accounting Standards Board’s (IPSASB) due process by using a multi-issue and -period analysis of comment letters (CLs) received by the IPSASB (2005-2018). It focuses on respondents’ affiliation and geographic background to assess whether the input received by the IPSASB is (un)representative for its stakeholders. It explores the influence of three variables to explain differences between stakeholders’ participation: IPSAS implementation level, English-proficiency, economic development level. The results evidence that the input is unrepresentative for all its stakeholder, which may influence the IPSASB’s input legitimacy, and complicate further IPSAS implementation. Stakeholders with higher economic development levels and higher IPSAS implementation levels participate more. Additionally, two factors in the due process are analysed to measure their influence on overall stakeholder participation: type of consultation documents, and length of comment periods. Longer comment periods have a positive influence on stakeholder participation.

Line Loss Reduction by Optimal Location of Battery Energy Storage System for the Daily Operation in Microgrid with Distributed Generations

Distributed generations (DGs) such as solar and wind generations are used as generation source in the microgrid. Due to the fluctuation of renewable energy sources, the battery energy storage system (BESS) is one of the essential components to control and improve the quality of power microgrid. However, a placement for BESS installation with minimizing line loss is one of the most concern problems. This paper aims to determine the optimal location of the BESS by using the analytical method with the line loss sensitivity index. A multi-period optimal power flow (OPF) and line loss analysis with BESS parameters were investigated considering the daily operation of a microgrid in connected mode. The simulation performed on the microgrid that wants to keep total power generation from DGs in BESS and low energy consumption from the utility. Microgrid includes 3 DGs (biomass, solar and wind turbine generators) to assess the robustness of BESS placement. The results confirmed the effectiveness of the presented method. The optimal location of BESS can reduce line power loss and power consumption from the utility.

The Ties That Bind: Materiality, Identity, and the Life Course in the "Things" Families Keep.

Using an interdisciplinary research methodology across three archaeological and historical case studies, this article explores “family archives.” Four themes illustrate how objects held in family archives, curation practices, and intergenerational narratives reinforce a family’s sense of itself: people–object interactions, gender, socialization and identity formation, and the “life course.” These themes provide a framework for professional archivists to assist communities and individuals working with their own family archives. We argue that the family archive, broadly defined, encourages a more egalitarian approach to history. We suggest a multiperiod analysis draws attention to historical forms of knowledge and meaning-making practices over time.

Stable Value Funds Performance

Little in the scholarly economics literature is directed specifically to the performance of stable value funds, although they occupy a leading place among retirement investment vehicles. They are currently offered in more than one-third of all defined contribution plans in the USA, with more than $800 billion of assets under management. This paper rigorously examines their performance throughout the entire period since their inception in 1973. We produce a composite index of stable value returns. We next conduct mean-variance analysis, Sharpe and Sortino ratio analysis, stochastic dominance analysis, and optimal multi-period portfolio composition analysis. Our evidence suggests that stable value funds dominate (on average) two major asset classes based on a historical analysis, and that they often occupy a significant position in optimized portfolios across a broad range of risk aversion levels. We discuss factors that contributed to stable value funds’ past performance and whether they can continue to perform well into the future. We also discuss considerations regarding whether or not to include stable value as an element in target date funds within defined contribution pension plans.