论建设项目前期的工程造价合理确定

投资估算是控制工程造价的源头，是开展工程造价管理后续工作的关键，尤其在工程建设投资多元化的当今，能否合理确定投资估算、设计概算，将影响到投资资金筹措和计划的落实。章就如何合理地确定工程造价提出了建议。     

Assessment of stock size to minimize cutting stock production costs

A method for assessing the optimal stock size for the expected order size for a single-period one-dimensional cutting stock problem is proposed. The stock size is optimal when the expected total costs of trim loss, warehousing, and non-fulfilment are minimum. The stock size is the sum of all bar lengths in the stock, and the order size is the sum of shorter bar lengths in various numbers of pieces. Using simulated test cases, a statistical estimation of optimal stock size is conducted, which in our case is approximately 50% above the expected order. The proposed method can help company choose the appropriate level of stock to minimize their total costs.     

Manufacturing Plants' Use of Temporary Workers: An Analysis Using Census Microdata

Using plant‐level data from the plant capacity utilization survey, we explore how manufacturing plants' use of temporary workers is associated with the nature of their output fluctuations and other plant characteristics. We find that plants tend to use temporary workers when their output is expected to fall; this may indicate that firms use temporary workers to reduce costs associated with dismissing permanent employees. In addition, we find that plants whose future output levels are subject to greater uncertainty tend to use more temporary workers. We also examine the effects of wage and benefit levels for permanent workers, unionization rates, turnover rates, seasonal factors, and plant size and age on the use of temporary workers; based on our results, we discuss various views of why firms use temporary workers.     

Smoothing, Nonsynchronous Appraisal and Cross-Sectional Aggregation in Real Estate Price Indices

In this article three econometric issues related to private-equity return indices, such as real estate indices, are explored (smoothing, nonsynchronous appraisal and cross-sectional aggregation). Under certain assumptions, it is found that index returns based on appraisals follow an ARFIMA(1, d , 1) (autoregressive fractionally integrated moving average) process, where the long memory parameter ( d ) explains the level of smoothing and the AR and MA parameters represent the level of persistence in marketwide fundamentals and the nonsynchronous appraisal, respectively. The empirical results show that: (1) the level of smoothing in appraisal-based real estate indices is far less than assumed in many academic studies (2) there is weak evidence of nonsynchronous appraisal in the UK, IPD (Investment Property Databank) index and (3) marketwide fundamentals are highly persistent for the IPD index returns. On the other hand, there is no evidence of nonsynchronous appraisal or a persistent common factor in the U.S. NCREIF (National Council of Real Estate Investment Fiduciaries) index.     

Empirical studies of entry and exit: A survey of the evidence

Over 70 empirical studies of entry and exit patterns covering eleven different countries generally support the expectation that entry is more frequent in more profitable, rapidly growing industries, and slower where the absolute costs of capital required to build a minimum efficient scale plant are imposing. Scale economies, excess capacity, and limit pricing receive little empirical support as entry impediments. The evidence concerning the effects of advertising and R&D intensity is confusing.Exit is faster where profits are lower, and slower where durable specific (sunk) capital costs are more important. Exit and entry are strongly correlated, probably due to displacement (of incumbents by more efficient entrants) and vacuum effects (in which entrants are enticed by the prospects of selling to uncommitted customers abandoned by a recent exit).     

Inside Ownership, Risk Sharing and Tobin's q-Ratios: Evidence from REITs

We investigate relations among inside ownership, managerial expenses, risk sharing and equity valuations. Our engine of analysis—Real Estate Investment Trusts (REITs)—provides a unique and rich framework for analysis since we can calculate extremely accurate measures of asset replacement costs, and hence relative valuation (Tobin's q ). Further, the nature of the financial statements allows us to examine the impact of insider ownership on agency costs since we can accurately measure the costs of the entire management team. Our results show that firms with greater insider holdings tend to invest in assets with lower systematic risk and use less debt in their capital structure. At the same time, managerial expenses are lower as inside ownership increases. Finally, higher levels of insider ownership are associated with higher relative valuation as measured by both higher premiums to net asset value and higher multiples of cash flows. The results have implications for the design of optimal management contracts for both REITs and firms in general.     

Model and analysis of integrated production–inventory system: The case of steel production

The study originated from an industrial case study in the field of steel production, but it presents a larger interest, as many other manufacturing fields have similar concerns (e.g. foundries, food, textile and paper industries). A significant phase of steel manufacturing is the product cooling (likewise, drying in paper and textile production, or maturing in food production). This phase may be completed in different ways, but (1) it must be carried out in the finished product warehouse and (2) it must meet both production optimisation and customer needs. The latter requirement acquires a strategic relevance in JIT environments. The present study proposes a mathematical model to find the optimal production schedule of steel billets, based on the relevant parameters of the productive system (set-up and processing times, demand profile). In the industrial case examined, the negative impact of holding costs on cash flows is also linked to the space required by the cooling process, which depends on the production schedule adopted. In other words, the finished product storage can be considered a part of the manufacturing cycle and impacts on it. In the case of steel plants operating in JIT environments, the warehouse must be promptly emptied and carefully managed to exploit the available space. Thus, the effect of inventory costs is examined in a production–inventory system with finite capacity, where products are made to order and share the same manufacturing facility. The study is completed by an experimental analysis to investigate the effect of variations in the relevant parameters of the problem.     

THE EFFECTS OF CAPACITY ON SALES UNDER ALTERNATIVE VERTICAL CONTRACTS*

Retailer capacity decisions can impact sales for products by affecting, for example, availability and visibility. Using data from the U.S. video rental industry, we report estimates of the effect of capacity on sales under alternative vertical contracts. New monitoring technologies facilitated new supply contracts in this industry, reducing upfront costs of capacity but requiring minimum capacity purchases, strongly impacting stocking decisions. We find that larger capacity (more tapes) for a given title can substantially increase rentals of that title; and that alternative vertical contractual forms for distributing tapes from studios to retailers strongly impacts the relationship between capacity and rentals.     

Reliability evaluation and adjustment of supply chain network design with demand fluctuations

This study focuses on supply chain network design problems by considering economies of scale and demand fluctuations. A reliability evaluation method is developed to evaluate the performance of plants under demand fluctuations. In addition, two mathematical programming models are developed to determine the optimal adjustment decisions regarding production reallocation among plants under different fluctuating demands. The judgments to adjust or to do-nothing are investigated by comparing the results if the adjustment is made or not made. Results show that making adjustments benefits the manufacturers by reducing total production cost and avoiding revenue loss, which outweighs the extra costs, especially for high value-added products. Results also suggest that the manufacturer should ignore a short period abnormal state, since the benefits to respond to it might not compensate the high allocation costs. The results of this study provide a reference for the manufacturer in their decision making process of network planning with demand fluctuations, when they have to cope with benefits and costs during abnormal states.     

Accelerating the Process of Engineering Change Orders: Capacity and Congestion Effects

Engineering change orders (ECOs) are important drivers of development costs and lead time. This article analyzes the process of administering engineering change orders in the case of the climate control system development within a large vehicle development project. This administrative process encompasses the emergence of a change (e.g., a problem or a market-driven feature change), its management approval, and final implementation. Despite strong time pressure, this process can take several weeks, several months, and, in extreme cases, even over 1 year. Such a long lead time is especially remarkable as the actual processing time for the change typically does not exceed 2 weeks. Based on our case study, we develop an analytical framework that explains how such an extreme ratio between theoretical processing time and actual lead time is possible. The framework identifies congestion, stemming from scarce capacity coupled with processing variability, as a major lead time contributor. We outline five improvement strategies that an organization can use in order to reduce ECO lead time, namely, flexible capacity, balanced workloads, merged tasks, pooling, and reduced setups and batching. © 1999 Elsevier Science Inc.     

Vergleichende Analyse der technisch-wirtschaftlichen Bedingungen von PV-Anlagen Mit Süd- und Ost-West-Ausrichtung

PV power plants with east-west-orientation have a lower energy production per installed kW_p due to their orientation than those facing to south. Thus they need a reduction of costs to compensate the lack of energy production and to have the same cost effectiveness as PV plants with south-orientation. This paper tries to show, how and if PV plants with east-west-orientation can be more profitable than PV plants with south-orientation. Therefore, the energy production was simulated for PV plants with an orientation to east-west and to south with different inclinations in a place with high irradiation (Freiburg) and a place with low irradiation (Hamburg). A calculation of profitability was made for each PV plant including energy production as well as ascertained costs. This are the main outcomes:

The profitability of PV plants with east-west-orientation is not better than the profitability of PV plants with south-orientation.

The profitability of PV plants with east-west-orientation is better than the one of PV plants with south-orientation when the costs of mounting systems are much lower for east-west mounting-systems than for mounting-systems with south-orientation and the costs of grid-connection and rent are high too.

The profitability of PV plants with east-west-orientation is higher in regions with low irradiation.

     

300MW空冷发电机与水氢氢冷发电机技术经济比较

300MW级发电机普遍采用水氢氢冷却方式,全空冷方式发电机由于辅助系统简单,在发电厂运行、维护及安全等方面有着明显的优点,但亦存在着投资较高、效率略低的问题。通过对空冷发电机及水氢氢冷却发电机的技术经济指标比较,提出了单台空冷发电机基于一定寿命周期的边界价格。     

Efficiencyv. collusion: Evidence cast in cement

Through the 1970s and 1980s, the U.S. portland cement industry experienced a significant increase in average plant size and market concentration. A simultaneous equation model is developed to examine the effects of plant size and concentration on costs, prices and margins in that industry. The results indicate the presence of significant scale economies, but also show that prices and margins are increasing in concentration. Further analysis shows that almost one third of the cost savings associated with larger plants are passed on to producers through higher margins resulting from concomitant increases in concentration, rather than to consumers as lower prices.     

“十五”期间我国乙烯工业的发展趋势

世界乙烯工业发展迅速，2000年世界乙烯生产能力已达92.7Mt/a。我国乙烯工业经过30年的发展，初具规模，但自给率偏低，发展空间和潜力十分巨大。“十五”期间，我国乙烯工业将面临加入WTO以后的激烈竞争，为此以中外合资建设运营大型乙烯项目为契机，引进跨国石化企业的先进技术和科学管理经营方式，加速国内乙烯工业的发展，合理选择现有乙烯装置进行改扩建，优化原料，降低成本，提高乙烯装置的竞争能力。     

Determining the Maximum Hourly Demand of Natural Gas for Large Suppliers

This article deals with the determination of the maximum hourly energy consumption of large (municipal) natural gas suppliers using the Monte Carlo simulation method. To ensure an adequate supply for all their customers, suppliers need to purchase capacities in geological storage systems. If, due to cost considerations or inaccurate predictions, the chosen capacities are smaller than the actual consumption, additional costs are incurred for the procurement of short-term quantities of gas, e.g. from the balancing energy market. It is therefore necessary to formulate and solve an optimisation problem, which is done as described in the following by means of a simulation after modelling all required quantity values and price data. The aim is to minimise the structure costs—i.e. the fixed capacity costs and the variable balancing energy costs—by selecting the most appropriate hourly energy supply level. Since the selection of the storage capacity generally has far-reaching financial implications, the statistics-based simulation method described in the following is intended to provide the companies concerned with a reliable basis for decision-making.     

Gleichzeitigkeit als Leistungsgröße: Inter- und Intra-Klassen-Leistung volatiler EE-Einspeiser

The energy transition focuses on the expansion and enhancement of distribution grids and the integration of decentralized renewable generation plants. The integration of decentralized plants presents a major challenge for distribution system operators in particular. The planning and dimensioning of energy grids requires knowledge of all integrated generating units and power consumers, as well as their power ratings. Furthermore, knowledge about the diversity of renewable power plant types enables distribution system operators and scientists to selectively or cumulatively assess the maximum feed-in capacity. This is particularly important for the assessment of case studies or border scenarios. The purpose of this article is the evaluation of the maximum simultaneous feed-in power of PV and wind power plants. Furthermore, the ratio of the installed power to the maximum power generated by renewable power plants is also investigated. The diversity factor describes the ratio of the sum of all individual load’s maximum powers to the number of loads. This simultaneity can also be adapted to renewable power plants. However, it is differentiated here between simultaneous power within one renewable power plant type (intra-class performance) and simultaneous power of different renewable power plant types (inter-class performance). In cooperation with one of the largest national distribution network operator, regression lines are approximated by statistical analyzes, in order to determinate the diversity of the Central German area.     

低硫与含硫原油加工经济效益分析

2004年以来全球石油需求大幅增加，特别是低硫原油需求十分旺盛，造成低硫与含硫原油的价差创下历史新高。文章分析了低硫原油与含硫原油价差扩大的原因，并从炼油毛利和加工成本等方面对两种原油的加工经济效益进行了剖析，提出了大力发展炼油加氢工艺、提高含硫原油加工能力是今后炼油厂发展的必然趋势。     

The possibility of price umbrellas in Canadian manufacturing industries

The paper looks for evidence of ‘price umbrelias’ within Canadian manufacturing industries. Price umbrellas occur when relatively low-cost firms, trading-off market share against profit margins, set a price high enough to allow relatively high-cost firms to remain in business (the latter have an ‘umbrella’ held over them). The disaggregated data appear to show (1) that there are significant differences in average costs between the plants within an industry, (2) that the marginal costs of the low-cost plants are non-increasing with output. Together, these findings imply that output could be transferred from high- to low-cost plants with a reduction in total-industry costs, consistent with the existence of price umbrellas. The numbers are quite large.     

Impacts of Subsidized Security on Stability and Total Social Costs of Equilibrium Solutions in an N-Player Game with Errors

Investment in defense by all agents is a socially optimum equilibrium in many interdependent security scenarios. However, practically, some agents might still choose not to invest in security due to bounded rationality and errors, thus decreasing the total social welfare. Previous work shows that providing subsidies may help induce more agents to invest. Our study suggests that giving subsidies to agents prone to making an erroneous choice could increase the stability of the socially optimum equilibrium, as well as decrease the total social costs.     

Einfluss der CO2-Zertifikatspreise auf die Stromgestehungskosten im deutschen Energiemix

In the past, electricity generation costs in Germany’s energy mix depended for the most part on the development of fossil fuel prices. Despite the strongly increasing share of renewable energies in the energy mix, the generation of electricity from fossil fuel power plants, especially brown and bituminous coal power plants, still dominates in Germany today. Alongside fossil fuels as an increasing cost factor, the price of CO₂ is also gaining importance as a price factor in the production of electricity from fossil fuel power plants. The establishment of the European Emission Trading Scheme (EU ETS) in 2005 formed the basis of CO₂ emissions pricing, and was oriented on the emission reduction targets of the European Union. Although the price of CO₂-certificates in free trade is shown on several stock exchanges, the CO₂ price is still policy driven. The amount of free allocated and traded CO₂-certificates is set on a European policy level. Current decisions on temporary limitations of the trade volume have corresponding effects on exchange prices. This article aims to investigate the impact of CO₂-certificate prices on electricity generation costs in the German energy mix. Comparing real CO₂ prices to forecasts for 2013 provides findings on the effects that the political decisions of the European Parliament with regard to the limitation of the trade volume of available CO₂-certificates have on electricity generation costs in the German energy mix.