on the structure of lost sales inventory models we provide a new approach to the structural analysis of the standard lost sales inventory system this approach is we think easier to work with than the original one we also derive new bounds on the optimal policy then we show that more variable demand leads to higher cost finally we extend the analysis to several important variations of the basic model

parametric replenishment policies for inventory systems with lost sales and fixed order cost in this paper we consider a single item inventory system with lost sales and fixed order cost we numerically illustrate the lack of a clear structure in optimal replenishment policies for such systems however policies with a simple structure are preferred in practical settings examples of replenishment policies with a simple parametric description are the s s policy and the s nq policy besides these known policies in literature we propose a new type of replenishment policy in our modified s s policy we restrict the order size of the standard s s policy to a maximum this policy results in near optimal costs furthermore we derive heuristic procedures to set the inventory control parameters for this new replenishment policy in our first approach we formulate closed form expressions based on power approximations whereas in our second approach we derive an approximation for the steady state inventory distribution as a result the latter approach could be used for inventory systems with different objectives or service level constraints the numerical experiments illustrate that the heuristic procedures result on average in 2 4 percent and 1 8 percent cost increases respectively compared to the optimal replenishment policy therefore we conclude that the heuristic procedures are very effective to set the inventory control parameters

understanding china s renewable energy technology exports abstract china became a major player in renewable energy re technology during the 2000s chinese solar pv cell and module makers quickly dominated global sales in that industry while the country s wind turbine producers became poised for significant exports after capturing their rapidly growing home market in countries like the us chinese re technology strength has been met with claims of excessive governmental support of exports this study examines to what extent chinese firms solar pv and wind technology successes have been enabled by policy supports and whether those policies appear to have been driven by broader goals versus re export promotion per se the evidence suggests that governmental policy toward both wind and solar originated in a push for export competitive chinese companies but the specifics differed substantially due to the particular requirements of building technological capabilities in each export readiness necessitated substantial support for domestic installation of wind but not solar pv power the findings also suggest that as the decade of the 2000s progressed environmental goals played an increasing role alongside export promotion in motivating and shaping chinese re technology policies

the effects of work sharing on employment and overtime in finnish manufacturing 1960 87 comparison of three alternative models the purpose of this paper is to develop a model of the determination of hours and employment is developed and compared with the models of brunello 1989 and hart and wilson 1988 the models are estimated by using annual and quarterly data from the finnish manufacturing sector according to the results the actual hours closely follow the standard hours this implies that the interior solutions in hours determination suggested by compared models are not relevant instead firms try to avoid overtime as a consequence work sharing through shorter hours will be effective

technical note on the quasiconcavity of lost sales inventory models with fixed costs we show that under a set of conditions both the maximal profit function and the objective function in several lost sales inventory models with fixed costs are quasiconcave not only is the quasiconcavity property useful computationally it also leads to a sharper characterization of the optimal policies neither the proof of the quasiconcavity property itself nor the proof of the optimal policies by using the property requires the machinery of k concavity or any of its k related extensions and hence they are intuitively appealing

work sharing employment and wages the paper analyzes the effects of a reduction in working time on wages and employment with a monopoly union in general it is not clear in which directions these variables move but if employment and working time are perfect substitutes the effects are related to how working time has been determined initially the wage increases if initial working time is smaller than or equal to the trade union optimum whereas the result is unclear when it is larger in this case it is never optimal for a trade union to reduce both the wage and working time in response to a recessionary supply shock the analysis may help to explain varying attitudes towards work sharing in different countries

wages hours and overtime premia evidence from the british labor market unlike the united states britain has no national laws regulating overtime hour assignment or compensation using individual level data on male non managerial workers from the 1998 british new earnings survey the authors investigate relationships among the standard hourly wage rate hourly earnings including overtime the overtime premium and the length of overtime hours they find that when overtime is accounted for average hourly wage earnings are fairly uniform across firms in a given industry because firms paying below market level straight time wages tend to award above market level overtime premiums and conversely firms paying above market level straight time wages provide below market level overtime premiums

asymptotic optimality of order up to policies in lost sales inventory systems we study a single product single location inventory system under periodic review where excess demand is lost and the replenishment lead time is positive the performance measure of interest is the long run average holding cost and lost sales penalty cost for a large class of demand distributions we show that when the lost sales penalty becomes large compared to the holding cost the relative difference between the cost of the optimal policy and the best order up to policy converges to zero for any given cost parameters we establish a bound on this relative difference numerical experiments show that the best order up to policy performs well yielding an average cost that is within 1 5 of the optimal cost when the ratio between the lost sales penalty and the holding cost is 100 we also propose a heuristic order up to level using two newsvendor expressions in our experiments the cost of this order up to policy is 2 52 higher on an average than the best order up to policy

the turning points of carbon kuznets curve evidences from panel and time series data of 164 countries with the dramatic economic development global warming caused by carbon emission has become increasingly serious and carbon emission reduction therefore comes to be the principle in most countries turning point tp which represents carbon emission turns from increasing to decreasing tendency with the economic growth has become a major focus of political and academic concern however previous studies on tp were contextualized only in individual countries or regions but barely from a global perspective which are insufficient for solving the carbon emission as a global issue therefore this study aims to provide a global picture of the carbon emissions by identifying the tps of 164 countries and five panel groups i e global high income upper middle income lower middle income and low income levels in the world and the patterns of them the results show that 123 individual countries and all the five panel groups accept the carbon kuznets curve ckc hypothesis then the tps of them are identified in particular three close correlations are identified throughout the study 1 the proportion of the ckc hypothesis and income level i e the higher income level the larger proportion of countries meeting the ckc hypothesis 2 the tps and income level i e the higher income level the higher tp and 3 the turning years and income level i e the higher income level the shorter turning years the identified tps in this study provide valuable references for not only individual countries but also countries at different income levels to tailor their strategies and policies to finally achieve global carbon emission reduction

the 35 hour workweek in france straightjacket or welfare improvement workweek reduction laws may be beneficial if market interactions do not fully take into account the preferences reflected in declining secular trends in working hours the most recent law in france shortened the workweek from 39 to 35 hours in 2000 for large firms and in 2002 for small firms analysing differences between large and small firm employees before and after the law we find that aggregate employment was unaffected but labour turnover increased as firms shed workers who became more expensive survey responses indicate that the welfare impact of the law was different across groups of workers women but not men may have benefited from coordination to a shorter workweek and there is also evidence of negative welfare effects for managers possibly due to the law s administrative burden marcello estevao and filipa sa

career concerns contracts and effort distortions a two period career concerns model with symmetric information but uncertainty about each worker s ability is analyzed contracts are unobservable but incomes are observable it is shown that effort is distorted upward by contracts being unobservable and that the distortion depends positively on turnover

review of renewable energy investment and financing in china status mode issues and countermeasures abstract with the support of national policies china s renewable energy generation industry has experienced a rapid development period and entered the world forefront level especially in the aspects of installed capacity and speed of newly installed capacity however with the rapid development of renewable energy the power generation industry is facing more and more challenges particularly in investment and financing as for wind power industry there are also some problems such as single financing channels blindness of projects investment and so on which will result in financing difficulties for some advanced projects in addition the problems for the investment of photovoltaic pv power generation leads to vicious competition and a tumble in international market thus the overcapacity of china s entire pv industry emerges generally speaking the renewable energy industry is facing a seemingly contradictory predicament of funding deficiencies and blind investment which is derived from the government centered renewable energy investment and financing this government centered mode has promoted the development of renewable energy industry in the early stage but it cannot be adapted to the requirements of sustainable development in view of these the problems of renewable energy investment and financing are deeply studied in this paper this paper proceeds as follows firstly the overview of the development of china s renewable energy industry is briefly introduced secondly the status quo of china s renewable energy investment and financing is explored in detail based on overview of the following five perspectives investment situation investment and financing bodies investment and financing means sources of funding and financing channels secondly the patterns and characteristics of renewable energy financing are summarized and a comparative analysis of wind power and photovoltaic power generation financing means is carried out finally renewable energy investment and financing issues are discussed and further feasible proposals are put forward in all this paper is of great significance in the sustainable and healthy development of china s renewable energy

hours layoffs and unemployment insurance funding theory and practice in an international perspective the strikingly different behaviour of important economic aggregates in the united states and other industrial countries has received surprisingly little attention from economists among recent exceptions however gordon i 982 has shown that wages and hours of work are much more flexible in the united kingdom and japan than in the united states such relative hours variability is confirmed in a macro analysis by capdevielle and alvarez i98i and at micro level by sengenberger and kohler i982 the latter authors are concerned with labour market adjustment within the u s and west german automobile industries between i 97 i and i 980 estimates of the german workeroutput elasticity are found to be less than half that of the united states while the german hours elasticity is twice the united states figure at the national aggregate level capdevielle and alvarez also reveal much greater employment variability in the united states than in most other oecd countries in the years following the i973 74 opec supply shock much in line with these employment hours observations moy and sorrentino i98i argue that after

work sharing and overtime this paper deals with the employment effects of reduced working time when firms endogenous response of overtime is considered the analysis distinguishes between fixed and profit maximizing levels of output as well as between interior and corner solutions it is shown that under plausible assumptions a reduction in working time is quite likely to be counterproductive as an employment promoting measure i introduction a reduction in working time has been proposed as a method of increasing employment through work sharing such proposals however often seem to build on an oversimplified view of the world where little consideration is given to various possible repercussions most economists therefore seem rather sceptical towards such proposals for more or less critical discussions see e g hart sloane 1979 charpin 1984 brunstad holm 1984 calmfors 1985 hoel 1986 1987 hoel vale 1986 and dreze 1987 none of these papers however takes into account that actual working time will differ from normal working time to the extent that there is overtime work the aim of this paper is to analyse how endogenous responses of overtime may affect the outcome with respect to employment of reducing the normal working time although overtime work currently accounts for only a minor proportion of total working time around three per cent in sweden we believe this to be an important channel since a major reduction in working time will represent a nonmarginal change which is likely to produce significant changes in established practices our results add to the doubts that a reduction in working time increases employment there has been some recent work on the relationship between normal working time and overtime cf hart 1984 fitzroy hart 1985

using alsace moselle local laws to build a difference in differences estimation strategy of the employment effects of the 35 hour workweek regulation in france france s 1998 implementation of the 35 hour workweek has been one of the greatest regulatory shocks on labor markets few studies evaluate the impact of this regulation because of a lack of identification strategies for historical reasons due to the way alsace moselle was returned to france in 1918 the implementation of france s 35 hour workweek was less stringent in that region than in the rest of the country which is confirmed by double and triple differences yet it shows no significant difference in employment with the rest of france which casts doubt on the effectiveness of this regulation

the impact of government subsidies and enterprises r d investment a panel data study from renewable energy in china in this research we aim to understand the influence of government subsidies on enterprises research and development r d investment behavior particularly in china s renewable energy sector we are also interested in examining how the attributes of enterprise ownership act as a moderating variable for the relationship between government subsidies and r d investment behavior three classical panel data analysis models including the pooled ordinary least squares ols model the fixed effect model and the random effect model are employed we find that government subsidies have a significant crowding out influence on enterprises r d investment behavior and that the influence is further moderated by the attributes of enterprise ownership moreover a panel threshold regression model is used to demonstrate how the influence of government subsidies on enterprises r d investment behavior will change when government subsidies increase two thresholds 0 6 and 10 1 are identified we recommend that relevant government departments should motivate enterprise r d investment behavioral intention by increasing subsidies within a certain range different attributes of enterprise ownership should also be considered as part of policy reform and re structuring relating to government subsidies

economic theory and the world of practice a celebration of the s s model it was the question of how best to balance the costs of ordering and of running out of stock against the costs of holding excess inventory that inspired kenneth arrow theodore harris and jacob marschak to introduce the s s model in 1951 in this celebratory article we show how this model not only answered important practical questions but also opened the door to a quite startling range of important and challenging follow up questions many of great practical importance and analytic depth the s s model has become one of the touchstone models of economics opening new vistas of applied economic theory to all who internalize its structure today it is universally applied to solve questions faced in inventory control the core model elements uncertainty and fixed costs of adjustment are ubiquitous which has resulted in its becoming the general purpose economic model of discrete adjustment the s s model has also become a profound source of inspiration for macroeconomists seeking to understand the role that discrete microeconomic adjustments play in macroeconomic fluctuations looking forward we foresee rapid growth in the use of s s modeling to aid households making complex and costly financial decisions such as when and how to terminate a mortgage in the projected era of household operations research new modeling challenges will arise due to enriched feedback from the world of practice

employment and allocation effects of reducing the length of the workday the paper analyses the effects of reducing the length of the workday in a situation with classical unemployment owing to a fixed hourly real wage rate the length of the workday is assumed to enter the production functions of the two sectors manufacturing and services differently employment will increase in the manufacturing sector while the employment effect in the service sector is ambiguous it is possible for employment in the service sector to decline so much that total employment also goes down if the workday is shortened in the manufacturing sector alone employment will rise in this sector and decline in the service sector the effect on total employment is ambiguous with a specific case of mixed classical and keynesian unemployment employment in the manufacturing sector will be unaffected by changes in the length of the workday while a reduction in the length of the workday will reduce employment in the service sector if the income elasticity for services is not less than one

effects of shorter hours on employment in disequilibrium models abstract in this paper the employment effects of a wage compensated and non compensated reduction of standard working time are examined in the context of disequilibrium theory in disequilibrium models with exogenous working time noncompensated shorter standard hours increase employment in both regimes keynesian and classical unemployment wage compensation reduces the employment response at a regime dependent rate if working time is endogenized by taking into account overtime effects the employment response of shorter hours is positive in keynesian unemployment and negative in classical unemployment wage compensation increases the employment effect in the keynesian regime and decreases it in the classical regime a model is presented that allows for hours as well as capital stock adjustment and integrates non competitive price setting

china s renewable energy law and its impact on renewable power in china progress challenges and recommendations for improving implementation beginning in 2006 china experienced a rapid growth in its renewable energy resources particularly wind power placing it among the world s leading countries in terms of renewable energy installation and generation this growth was greatly enabled by the renewable energy policy framework created by its landmark renewable energy law passed in 2005 and amended in 2009 which established key policies including national renewable energy targets a mandatory connection and purchase policy a national feed in tariff system and arrangements for cost sharing and funding of renewable energy incentives this paper describes the mechanisms established by the renewable energy law and its implementing regulations as well as the challenges china continues to face in improving its renewable energy policy framework to improve integration and utilization of renewable energy sources it also provides a comparison of the chinese renewable energy policy framework with those in the european union and united states finally the paper provides recommendations for improving implementation of the renewable energy law with regard to implementing a renewable power quota system and priority dispatch policy developing technical standards for connection of renewable resources with the grid development of a more advanced feed in tariff system and central local coordination of renewable energy development

effects on unemployment of reduced working time in an economy where firms set wages the paper considers an economy where firms set wages balancing the direct benefit of low wages with the indirect cost of low wages relative to other firms leading to high quit rates and therefore high training costs reducing the institutionally given working time makes the importance of training costs increase thus making firms more concerned about keeping quit rates low the effect is increased unemployment as a consequence of reduced working time the effect on hourly and yearly wages is uncertain although increased hourly wages seem to be the most plausible case

a critical review of china s rapidly developing renewable energy and energy efficiency policies renewable energy and energy efficiency reee policies have far reaching implications for energy security climate change economic competitiveness pollution and human livelihood for these reasons reee has become a national priority for the chinese government particularly since 2005 this paper aims to critically review china s reee policies in six sectors electricity industry transportation buildings and local government in addition to examining the progress china has made in the development and implementation of reee policies this review also identifies limitations and room for improvement finally five policy recommendations are presented

periodic review lost sales inventory models with compound poisson demand and constant lead times of any length in almost all literature on inventory models with lost sales and periodic reviews the lead time is assumed to be either an integer multiple of or less than the review period in a lot of practical settings such restrictions are not satisfied we develop new models allowing constant lead times of any length when demand is compound poisson besides an optimal policy we consider pure and restricted base stock policies under new lead time and cost circumstances based on our numerical results we conclude that the latter policy which imposes a restriction on the maximum order size performs almost as well as the optimal policy we also propose an approximation procedure to determine the base stock levels for both policies with closed form expressions

the cost of overtime hours in british production industries both theoretical and empirical labour market papers that incorporate the workers hours dichotomy often contain assumptions about shapes of the overtime premium schedules faced by industry using cross section data for british production industries in three years of sharply contrasting economic climates 1981 1984 and 1988 this paper investigates empirically the appropriate choice of schedule and therefore the industrial cost consequences of changing the average number of overtime hours per period the analysis tackles problems associated with data disaggregation the proportion of workers working overtime omitted variables heteroscedasticity and intertemporal variation

employment and distributional effects of restricting working time we study the employment and distributional effects of regulating reducing working time in a general equilibrium model with search matching frictions job creation entails fixed costs but existing jobs are subject to diminishing returns we characterize the equilibrium in the de regulated economy where firms and individual workers freely negotiate wages and hours then we consider the effects of a legislation restricting the maximum working time while we let wages respond endogenously employment effects are sensitive to the representation of preferences in our benchmark small reductions in working time starting from the laissez faire equilibrium solution always result in a small increase in the equilibrium employment while larger reductions reduce employment the regulation benefits workers both unemployed and employed even if wages decrease and even in cases where employment falls but reduces profits and output

shaping china s energy security the impact of domestic reforms this paper is a subsequent study of china s energy security situation which concludes that china s energy security has not improved over 30 years of economic reform the objective of the study is to explore qualitatively why the energy security situation has not improved to answer the why question the study opens up a new perspective by analyzing the relationship between energy security and energy policies from the macroeconomic reform perspective this study discusses major reforms that took place over 30 years it is found that china s macroeconomic reform has restricted the formation of china s energy policies and determined its energy security situation in essence china s energy policies are only a reaction to the macroeconomic measures in other words china s energy policies are not originally intended to improve energy security but passive reactions to china s macroeconomic reform this explains why china did not improve its energy security situation despite 30 years of reform

the role of local private participation in china s transition to domestically developed renewable energy technologies china s hunger for energy has over the last two decades afforded opportunities to investors from hong kong and foreign countries to provide both the energy technologies china needs as well as project management capabilities to deliver energy projects recently however china has shown itself to be less reliant on non local expertise with an emerging capacity to go it alone in developing sources of energy data from the world bank private participation in infrastructure ppi database was used to analyse this trend and to identify strategic directions that may be evident in china s emerging energy self reliance a total of 555 cases were extracted for analysis using standard statistical tests across the range of available energy technologies while it was found that the involvement of hong kong and foreign companies remains significant overall there is a clear trend in chinese mainland firms targeting and overtaking non local counterparts in the development of renewable energy technologies and projects strong associations were identified between the rise in renewable projects and the growth in the participation of local companies in the energy sector this is a significant finding and it provides strong implications that chinese firms have emerged as an important competitor in renewable energy provision

testing the effectiveness of the french work sharing reform a forecasting approach the macroeconomic impact of the french work sharing reform of 2000 a reduction of standard working hours in combination with wage subsidies is analysed using a vector error correction model vecm for several labour market variables as well as inflation and output out of sample forecasts for 2000 2001 are produced a comparison of these forecasts which serve as a benchmark simulation without structural shifts to the realized values with shifts suggests significant beneficial employment effects of the policy mix other shifts were absent and thus cannot explain the outcome output productivity hourly labour costs and inflation are only transitorily affected or not at all

working time regulation in france from 1996 to 2012 france which is often seen as an unusual country with a rigid 35 hour working week has experienced massive changes in its regulation of working time in recent decades including a progressive removal of 35 hour working week laws these changes have affected and continue to affect workplace organisation working conditions job creation productivity and wages the 35 hour working week policy represents a reduction in working time as well as a complex package that restructured french labour law and that opened up a great deal of space for social bargaining this paper provides a comprehensive analysis of the evolution of working time regulation and its political roots it discusses the studies evaluating the 35 hour working week and examines some of the basic consequences of reversing this policy since 2002 it also highlights unexplored lines of research on this topic

work sharing during the great depression did the president s reemployment agreement promote reemployment the president s reemployment agreement pra of 1933 directed firms to reduce workweeks during the great depression so existing jobs could be spread into additional employment opportunities similar work sharing policies have recently been implemented across europe in hopes of reducing unemployment i find that ceteris paribus the work sharing aspects of the pra created nearly 2 5 million new employment opportunities in around four months however the programme also required firms to raise hourly wage rates offsetting close to half of these gains furthermore most of the remaining employment gains were wiped out after cartel oriented industry specific codes of fair competition supplanted the pra

models of labour services and estimates of total factor productivity this article examines the manner in which labour services are modelled in the aggregate production function concentrating on the relationship between numbers employed and average hours worked it argues that numbers employed and hours worked are not perfect substitutes and that conventional estimates of total factor productivity which by using total hours worked as the measure of labour services assume they are perfect substitutes will be biased when there are marked changes in average hours worked the relevance of the theoretical argument is illustrated using data for the united states and the united kingdom

employment and hours of work abstract this paper develops a dynamic model of the labor market in which the degree of substitution between employment and hours of work is determined as part of a search equilibrium each firm chooses its demand for working hours and number of vacancies and the earnings profile is determined by nash bargaining the earnings profile is generally nonlinear in hours of work and defines the trade off between employment and hours of work concave production technology induces firms to overemploy and as a result hours of work are below their optimal level the hosios condition is not sufficient for efficiency when there are two industries workers employed by firms with higher recruitment costs work longer and earn more that is good jobs require longer hours of work interestingly technology differentials cannot account for working hours differentials

the r q control of a periodic review inventory system with continuous demand and lost sales abstract in this paper we consider a periodic review inventory model with lost sales during a stockout and with the constraint that at most one replenishment order may be outstanding at any time demands in successive review periods are independent identically distributed variables from a continuous distribution the fixed lead time is an integral number of review periods we explore control policies of the r q type that is a replenishment order of size q is placed when the inventory position stock in hand plus stock on order falls to or below the re order level r we use asymptotic renewal theory results to estimate the undershoot of the re order level r and also to estimate the cycle stockholding cost which turns out to take a relatively simple form based on these approximations we set out a policy improvement solution methodology and illustrate this with some numerical examples for which demand is normally distributed these numerical examples suggest that a relatively simple approach based on the economic order quantity can provide results which are very close to optimal