Environmental risk factors contributing to traffic accidents in children: a case-control study

The aim of this study is to identify environmental risk factors related to road accidents in children of Tehran. This case-control study was performed in 2013. The cases were injured pedestrians aged 5–15 who were admitted to major hospitals supervised by Tehran University of Medical Sciences. The sample size for the cases was 273 and for the control group was 546. For the completeness of the clusters, 7 extra persons in case (total = 280) and 14 persons (total = 560) in control group were included. The interference of confounding variables assessed through forward conditional logistic regression. Result shows occurrence of traffic accidents was significantly associate with the width of the alleys or (<5 m: OR = 8.4, 95% CI: 3.3–21.5; 5–8 m: OR = 4.7, 95% CI: 1.8–12.2), distance from home to school((<100 m: OR = 1.7, 95% CI: 1.0–2.8), existence of parking lot (OR = 1.5, 95% CI: 1.0–2.3), traffic congestion (OR = 4.1, 95% CI: 2.6–6.4), traffic speed (OR = 2.1, 95% CI: 1.3–3.2) and existence of pedestrian bridges(OR = 4.2, 95% CI: 2.6–6.8). In the light of the important role of environmental factors in the occurrence of child traffic accidents, alleviating structural risk factors in addition to education and enforcement need more systematic efforts and planning by policymakers and urban planners to attain pedestrian safety goals.     

A computable general equilibrium model of international sanctions in Iran

We detail recent international sanctions against the Iranian economy and its government imposed by a subset of developed countries. The effects of these sanctions on the Iranian economy in general and upon upper and lower‐income rural and urban Iranian households, as well as the Iranian government, are modelled using a computable general equilibrium (CGE ) model. We supplement the Global Trade Analysis Project 8 data set using income and expenditure shares from the Urban and Rural Household Income and Expenditure Survey from the Statistical Centre of Iran (SCI ). The model is calibrated to simulate the effects of international sanctions as closely as possible. We use endogenous trade taxes to simulate the effects of sanctions on Iranian oil and petrochemical exports and Iranian imports of petroleum products, metal products and motor vehicles. Our study finds that international sanctions reduced aggregate Iranian welfare by 14%–15%. Rural households in Iran suffered welfare losses which were almost double those experienced by urban households, and the poorest urban and rural households experienced the largest welfare losses, in the order of 5%–10%. But the government of Iran sees a decrease in real revenue of 40%–50%, due to the large negative effect of sanctions on the Iranian oil sector.     

Reaching those at highest risk to fires and burns: Young children,older adults,and people in low-income communities

Injury specialists have not successfully convinced policy makers and the public that injuries can be controlled. That failure may be due in part to the lack of a unified understanding of injury control. The two most important models utilized in injury control are Haddon's Matrix1 and the Public Health Approach (PHA). This paper argues that the PHA should be combined with the two axes of Haddon's Matrix to result in a model that is coherent and comprehensive. Thus it is better than either one of the original models on their own. Haddon's Matrix has two axes. The first includes elements of the epidemiological triad, host, vector, and environment and likens injury to disease. The second axis includes three time intervals, pre-event, event, and post-event. The importance of including time was that injury was conceptualized as predictable and preventable. The weakness of Haddon's matrix is that it lacks a systematic plan of action. The Public Health Approach is a methodology for addressing injury, which consists of a hierarchy of four levels; surveillance, risk factor identification, intervention evaluation and program implementation. The use of the PHA with no specific orientation or means of application is its weakness. The PHA lacks a systematic point of application. Haddon's Matrix lacks a systematic action plan. Therefore we propose the PHA as the systematic strategy for the more theoretical framework of Haddon's matrix. By combining these concepts a coherent and comprehensive three-dimensional framework is defined. The unified model closes the potential gaps in the two original models and includes a systematic approach not previously achieved. This unified model is practical in defining individual studies and groups of studies. It can be used as an inventory, for a complete understanding of a particular injury. Diagrams of the model are presented to help teach the concepts of injury described in this unitary model. In conclusion, we can say that the inclusion of three injury concepts in one framework provides a rigorous and coherent construct for the understanding of injury and implementation of control activities. It can therefore be used to design more comprehensive programs for injury control and promote policies and funding commensurate with the magnitude of the injury problem.     

Assessing the impact of communication costs on international trade

Communication costs are frequently cited as an important determinant of trade costs. We test this relationship by incorporating alternative measures of communication costs in a model of bilateral trade. We find that international variations in communication costs indeed have a significant influence on trade patterns. Furthermore, estimates using disaggregated data reveal that communication costs are more important for trade in differentiated products than for trade in homogenous products.     

Risk assessment of maintenance operations: the analysis of performing task and accident mechanism

Maintenance operations cover a great number of occupations. Most small and medium-sized enterprises lack the appropriate information to conduct risk assessments of maintenance operations. The objective of this research is to provide a method based on the concepts of task and accident mechanisms for an initial risk assessment by taking into consideration the prevalence and severity of the maintenance accidents reported. Data were gathered from 11,190 reported accidents in maintenance operations in the manufacturing sector of Andalusia from 2003 to 2012. By using a semi-quantitative methodology, likelihood and severity were evaluated based on the actual distribution of accident mechanisms in each of the tasks. Accident mechanisms and tasks were identified by using those variables included in the European Statistics of Accidents at Work methodology. As main results, the estimated risk of the most frequent accident mechanisms identified for each of the analysed tasks is low and the only accident mechanisms with medium risk are accidents when lifting or pushing with physical stress on the musculoskeletal system in tasks involving carrying, and impacts against objects after slipping or stumbling for tasks involving movements. The prioritisation of public preventive actions for the accident mechanisms with a higher estimated risk is highly recommended.     

Speed-profile-based road segmentation for accident occurrence modelling for hilly terrains

Modelling the accident occurrences per unit length of the road requires segmentation of road stretch. In the case of hilly terrains, homogeneity-based approach results in extremely small sections thus creating a biased accident data. This result is due to the high variations in geometry along the length of the road stretch. Constant length sections do not consider the effect of road's characteristics, hence may lead to undesirable results. It is hypothesized that the speed profile of a vehicle moving in free-flow conditions is governed by the road geometry as well as the road side environment. In this paper, a new methodology based on speed profile of a test vehicle (passenger car) has been proposed for segmenting a road stretch passing through hilly terrain. Comparative analysis of the results obtained from the constant length segmentation approach and the proposed approach shows that the later approach is producing statistically better results. Relatively more parameters were found to be statistically significant in the model based on speed-profile-based segmentation. Grade length, which could be one of the major parameters in hilly terrains, was found to be statistically significant only in the model based on speed-profile-based segmentation.     

Relative effects of store traffic and customer traffic flow on shopper spending

This article examines the relative effects of store traffic and customer traffic flow on shopper spending in a single study. An analysis of Croatian hypermarket survey data indicates that store traffic alone does not adequately explain shopper spending. Instead, gross customer traffic flow and realized customer traffic flow are stronger drivers of money spent. The article contributes to the retailing literature by clarifying the respective roles of store traffic and customer traffic flow. Recognizing the greater revenue-generating effect of in-store traffic flow, retailers should better design their store layout and merchandizing strategies to optimize traffic movement and boost store performance.     

Control charts for accident frequency: a motivation for real-time occupational safety monitoring

This paper quantitatively motivates the need for active monitoring of occupational safety incident data through the use of cumulative sum (CUSUM) control charts. The frequency of incidents within a subset of historical accident data is analysed. The performance of Poisson CUSUM and exponential CUSUM (time-between-events) charts is compared in an illustrative example to show that shorter periods of aggregation and time-between-events monitoring lead to more timely indications of increased accident frequency. An extension showing the anticipated performance of these charts with real-time data is given. Various adjustments to the monitoring system are also simulated to show that quick implementation of hazard controls can significantly impact safety performance. Decreases in the frequency of safety incidents as a result of implemented hazard controls can also be monitored.     

The impact of traffic sign deficit on road traffic accidents in Nigeria

This study assesses the impact of traffic sign deficit on road traffic accidents in Nigeria. The participants were 720 commercial vehicle drivers. While simple random sampling was used to select 6 out of 137 federal highways, stratified random sampling was used to select six categories of commercial vehicle drivers. The study used qual-dominant mixed methods approach comprising key informant interviews; group interviews; field observation; policy appraisal and secondary literature on traffic signs. Result shows that the failure of government to provide and maintain traffic signs in order to guide road users through the numerous accident black spots on the highways is the major cause of road accidents in Nigeria. The study argues that provision and maintenance of traffic signs present opportunity to promoting safety on the highways and achieving the sustainable development goals.     

Laypeople roles at road traffic crash scenes: a systematic review

This study aimed to identify the roles of laypeople at road traffic injuries (RTIs). A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The key words of ‘laypeople’, ‘layman’, ‘layperson’, ‘bystander’, ‘first responder’, ‘lay first responder’, ‘road traffic’, ‘road traffic injury’, ‘crash injury’, ‘crash scene’, ‘emergency’, ‘trauma care’, and ‘prehospital trauma care’ were used in combination with the Boolean operators OR and AND. We did electronic search on Google Scholar, PubMed, ISI Web of Science, CINAHL, Science Direct, Scopus, ProQuest. Based on the reviewed studies, some factors such as cultural conditions, knowledge, relief agencies, and demographic factors affect the interventions of laypeople at the crash scene in functional areas. Regarding the permanent presence of people at the crash scene, the present study can provide an opportunity to reduce different side effects of RTIs imposed on the society.     

Evaluating performance of a Lead Road Safety Agency (LRSA) in a low-income country: a case study from Pakistan

The World Health Organization recommends identifying a Lead Road Safety Agency (LRSA) within the government to coordinate preventive interventions. As LRSAs in developing countries have rarely been evaluated, this case study describes the performance of the LRSA of Pakistan with respect to the World Bank criteria. The designated LRSA, the National Road Safety Secretariat, was put into operation in 2006 and worked for about two years with World Bank funding. The agency had a stand-alone structure headed by an experienced road safety specialist during the first year only and faced difficulty in recruiting other required experts. The LRSA drafted the first National Road Safety Plan, including strategic review of road safety and existing legislation, articulated multisectorial collaboration nationally and provincially, and collected traffic injury data in some districts. Its progress was halted by its dissolution because of funding problems. Currently, two agencies specialising in traffic enforcement and transport research respectively are fulfilling LRSA functions on an ad-hoc basis. Results suggest that sustainability and consistency of LRSAs in developing countries like Pakistan may only be ensured if they are legally protected, inter-ministerial, have permanent funding and are provided with the required expertise through international cooperation, so they can perform their required functions effectively.     

The newsvendor model revisited: the impacts of high unit holding costs on the accuracy of the classic model

The newsvendor problem has been applied in various business settings. It is often assumed that the decision variable, i.e., order-up-to level, has no impacts on the holding costs for average inventory cycled in a given period, which is the difference between beginning and ending inventory levels on hand in that period. The average holding cost for this portion of inventory is conveniently and approximately calculated as half the product of the unit holding cost and the expectation of the demand in one period if it is assumed that the inventory is approximately evenly consumed. It is a good approximation when the unit holding cost is significantly lower than the unit backorder cost as this optimal solution to inventory level is able to guarantee a low probability of understocking. However, if this condition does not hold, the approximation may deviate from the actual cost and cannot measure the expected holding cost for this portion of inventory. This paper examines the impact of the cycle stock holding cost on the newsvendor model and the conditions under which this portion of cost is not negligible.     

Aggregated analysis of in-depth accident causation data

Data collected from in-depth road accident investigations are very informative and may contain more than 500 accident-related variables for a single investigated case. These data may be used to get a more detailed knowledge on accident and injury causation associated with a specific accident scenario. However, due to their complexity, studies using in-depth data at aggregated levels are not common. The objective of this paper is to propose a methodology to analyse aggregated accident causation charts in order to highlight strong and weak relationships between crash causes and pre-crash scenarios. These relationships can be taken into account when developing or assessing new road safety measures (e.g. in-vehicle systems). The methodology has been applied to an in-depth accident dataset derived from the European project SafetyNet. Four different pre-crash scenarios associated with the accident scenario ‘vehicles encountering something while remaining in their lane’ have been investigated. Even if generalization of these results should be done with care because of database representativeness issues, the methodology is promising, highlighting, for example, a well-defined causation pattern related to vehicles striking a vehicle in rear-end accidents.     

Geographical disadvantage: a Heckscher-Ohlin-von Thünen model of international specialisation

We analyse the trade and production patterns of countries located at varying distances from an economic centre. Exports and imports of final and intermediate goods bear transport costs which increase with distance. We show how production and trade depend on factor endowments and factor intensities, and also on countries’ locations and the transport intensities of different goods. Countries divide into zones with different trade patterns, some export oriented and others import substituting. We study the implications of distance for factor prices and real incomes, the effects of changes in transport costs, and the locational choice of new activities.     

5G毫米波信道估计研究综述

信道估计是大规模多输入多输出（Multiple-Input Multiple-Output,MIMO）毫米波（Millimeter Wave,mmWave）系统关键技术之一。梳理了近几年大规模MIMO毫米波的信道估计策略,重点从压缩感知（Compressive Sensing,CS）、参数估计和深度学习三个方面进行了描述与分析。通过算法性能的对比,总结了毫米波信道估计目前存在的问题以及未来发展的趋势。     

Sectoral adjustment costs and real exchange rate dynamics in a two-sector dependent economy

This paper develops a two-sector model in which intersectoral capital movements involve adjustment costs, expressed as capital lost in the transformation process. These costs have important consequences for the dynamics of capital accumulation and particularly for real exchange rate dynamics. Persistent deviations of the real exchange rate from its equilibrium are derived and for plausible values of the adjustment cost parameters are consistent with the observed degree of real exchange rate persistence. For low adjustment costs the dynamics are qualitatively similar to those of the standard Heckscher-Ohlin technology. For high adjustment costs, the model converges to the specific-factors model. Thus our framework includes these two standard models as polar extremes.     

随机情景生成模型的参数估计

随机规划模型由于其自身的独特优势,在金融机构及个人的长期金融资产负债管理中的应用日益广泛,而对未来不确定性的合理刻画(通常被称为情景生成)是其成功应用的关键。随机微分方程是一种生成情景的重要方法,为了提高情景生成的质量,需要对模型参数进行精确的估计。与常用的一些模型参数估计方法相比,综合参数估计法是一种更具优势的方法。