曲面响应法预测砂浆性能的试验研究

本试验以砂浆性能为研究对象,采用Box-Behnken的中心组合实验设计及响应面分析方法对腻子粘结强度进行预测研究。试验选用三因素三水平的响应曲面分析法,建立了粘结强度的二次多项数学模型,并以粘结强度为响应值作响应面和等高线,考察了水粉比、灰粉比和胶粉比对粘结强度的影响,并根据实际选择响应曲面方程,利用最小二乘法估计相应的系数,剔除最不显著因素,建立最终的数学方程。结果表明:该预测模型能很好地描述粘结强度与水粉比、灰粉比和胶粉比之间的关系,可以对腻子粘结强度进行分析和预测,为砂浆性能研究提供一种新方法。     

DEMAND,CUSTOMER BASE‐LINE AND DEMAND RESPONSE IN THE ELECTRICITY MARKET: A SURVEY

The increasing use of demand‐side management, as a tool to reliably meet electricity demands at peak time, has stimulated interest among researchers, consumers and producer organiza‐tions, managers, regulators and policymakers. This research reviews the growing literature on models which are used to study demand, customer base‐line (CBL) and demand response in the electricity market. After characterizing the general demand models, the CBL, based on which the demand response models are studied, is reviewed. Given the experience gained from the review and existing conditions, the study combines an appropriate model for each case for a possible application to the electricity market; moreover, it discusses the implications of the results. In the literature, these aspects are studied independently. The main contribution of this survey is attributed to the treatment of the three issues as sequentially interdependent. The review is expected to enhance the understanding of the demand, CBL and demand response in the electricity market and their relationships. The objective is conducted through a combination of demand and supply side managements in order to reduce demand through different demand response programs during peak times. This enables electricity suppliers to save costly electricity generation and at the same time reduce energy vulnerability.     

Measurement of patient-reported outcomes. 1: The search for the Holy Grail

Abstract

Patient-reported outcome measures (PROMs) are used to collect information directly from patients. They may cover several different types of outcomes ranging from symptoms, functioning, utility, satisfaction, through to quality-of-life (QoL). They generally consist of self-completed questionnaires that can be administered by means of hard copies or in a range of electronic formats. PROMs vary considerably in terms of the constructs they assess, the care with which they are developed, and their scientific quality. However, none of the PROMs available approach the quality of measurement achieved by measures/instruments used in physics. PROs are examples of latent variables. These are not directly observable, but can be inferred from, for example, responses to a questionnaire. The only measure of a latent variable that approaches the quality of measurement achieved by the physical sciences is the Lexile Framework for Reading. This framework is based on a construct theory that grew out of an analysis of several available reading measures. A specification equation was generated that was able to link the construct theory to scores obtained with the Lexile measure. A fundamental requirement of this quality of measurement is that the data collected with the model fit Rasch Measurement Theory (RMT). It is argued that PROM developers should aspire to match this level of measurement sophistication if their instruments are to provide valid insights into the impacts of disease and its treatment.     

Minimising emergency response time of ambulances through pre-positioning in Dhaka city,Bangladesh

This study conducted a large-scale survey in Dhaka, Bangladesh; the survey involved 95 major hospitals, more than 3000 emergency room patients, and 2 of the largest ambulance operators. Currently, most ambulances are parked within the vicinity of hospitals and are either dispatched or fetched by the acquaintances of the patient on demand, resulting in lengthy round trips. Reducing the response time of ambulances would certainly improve the emergency service, and pre-positioning of the ambulances could be a solution to reducing the response time. This study used two approaches to address the problem. First, the location-allocation problem was solved to find the optimal number of ambulance locations by maximising the demand coverage. Second, separate location-allocation for the peak and off-peaks, using K-means clustering, was applied to systematically optimise the ambulance positioning in small clusters near demand points. These approaches could substantially improve the existing emergency response time. Distributing ambulances near demand points yielded greater improvements in response time than when the ambulances are stationed near hospitals.     

Risk analysis of the EASA minimum fuel requirements considering the ACARE-defined safety target

We present the results of flight simulator experiments (60 runs) with randomly selected airline pilots under realistic operational conditions and discuss them in light of current fuel regulations and potential fuel starvation. The experiments were conducted to assess flight crew performance in handling complex technical malfunctions including decision-making in fourth-generation jet aircraft. Our analysis shows that the current fuel requirements of the European Aviation Safety Agency (EASA) are not sufficient to guarantee the safety target of the Advisory Council for Aviation Research and Innovation in Europe (ACARE), which is less than one accident in 10 million flights. To comply with this safety target, we recommend increasing the Final Reserve Fuel from 30 min to 45 min for jet aircraft. The minimum dispatched fuel upon landing should be at least 1 h.     

The role of turboprops in China’s growing aviation system

The Chinese aviation system is in a period of rapid growth, with significant growth in second tier and emerging cities. Lower density cities could be well served by regional aircraft, either regional jets or turboprops, which offer different qualities and a different future for Chinese aviation. Turboprops offer a high level of fuel efficiency compared with regional jets which may improve the cost economics for carriers and reduce the air quality and climate impacts of a growing aviation system in a region where air quality and greenhouse gas emissions are a serious concern. However, regional jets are known for their superior quality of service and faster travel speeds. We begin with a spatial analysis of existing Chinese short-haul aviation networks and find that turboprops are deployed in limited number and are dispersed throughout the country. Their limited use, however, is not because of their cost economics. For the existing regional jet network we estimate the trade space of fuel and time for the replacement of regional jets with turboprops and find that all regional jet routes in China would generate savings if replaced with turboprops. We next establish future short-haul aviation routes between new and emerging airports and estimate the likelihood that a turboprop will be used. The finding that the most viable turboprop markets are spatially dispersed through the country validates considering turboprop investment at the state-level as a component of the established Chinese aviation sustainability initiative.     

A study on factors affecting privacy risk tolerance to prevent the spread of COVID-19 in South Korea

South Korea has been evaluated as a country that is responding well to COVID-19. The Government of the Republic of Korea discloses where, when, and by which means of transportation people confirmed to have the virus have visited. Although disclosure of movement has contributed to flattening the curve and providing timely medical service, concerns about privacy infringement have also been raised. This article determines what factors influence privacy risk tolerance, looking specifically at threat severity, vulnerability, response efficacy, and response cost. We also provide implications for the preparation of better countermeasures for the government to implement.     

Asset indexes and the measurement of poverty,inequality and welfare in Southeast Asia

Using data on household consumer durables from the Asian Barometer Survey, this paper examines the evolution of inequality, poverty and welfare in six countries of South East Asia: Cambodia, Indonesia, Malaysia, the Philippines, Thailand and Vietnam. We start by deriving the most common order of acquisition of these durables, using first an algorithm proposed by Paroush (1965), and then Item Response Theory. We also compute the frequency distribution of the number of durables owned by households. We then use these results to compute inequality, poverty and achievement or welfare indices adapted to the case of ordinal variables.Our empirical results confirm the existence of an order of acquisition. The results show that inequality was higher in Cambodia, Indonesia and the Philippines and lower in Vietnam, Thailand and Malaysia. A similar classification of countries was obtained when computing multidimensional poverty indices.Finally, using the welfare or achievement index recently introduced by Apouey et al. (2019), we found that welfare was generally higher in Vietnam, Thailand and Malaysia and lower in Cambodia, Indonesia and the Philippines.     

Prospect Theory,Fairness, and the Escalation of Conflict at a Negotiation Impasse*

We study a bilateral negotiation set-up where, at a bargaining impasse, the disadvantaged party chooses whether to escalate the conflict or not. Escalation is costly for both parties, and it results in a random draw of the winner of the escalated conflict. We derive the behavioral predictions of a simple social utility function, which is convex in disadvantageous inequality, thus connecting the inequity aversion and the prospect theory models. Our causal laboratory evidence is, to a large extent, consistent with the predicted effects. Among other things, the model predicts that the escalation rate is higher when escalation outcomes are riskier, and that the disagreement rate is lower when the cost of escalating the conflict is higher.     

Long‐term economic consequences of corporate environmental responsibility: Evidence from heavily polluting listed companies in China

In this study, we aim to investigate the long‐term economic consequences of corporate environmental responsibility (CER) by companies from the perspective of earnings persistence and investors' response. Based on firm‐level data of 1,010 heavily polluting listed companies in China, the empirical results are as follows. First, the CER of China's heavily polluting listed companies has significantly improved their earnings persistence, that is, earnings quality. Second, the positive long‐term economic effect of CER has been achieved through two paths: improving companies' operational efficiency and reducing their credit costs. Third, CER increases investors' response to heavily polluting companies' accounting earnings. Moreover, state‐owned listed companies achieve more significant positive long‐term economic effects from CER than others. The results suggest that heavily polluting companies should correctly identify the long‐term value of CER rather than pay excessive attention to the impact of CER on their current costs and benefits.