Effort estimates through project complexity

This paper reports the results obtained from use of project complexity parameters in modeling effort estimates. It highlights the attention that complexity has recently received in the project management area. After considering that traditional knowledge has consistently proved to be prone to failure when put into practice on actual projects, the paper endorses the belief that there is a need for more open-minded and novel approaches to project management. With a view to providing some insight into the opportunities that integrate complexity concepts into model building offers, we extend the work previously undertaken on the complexity dimension in project management. We do so analyzing the results obtained with classical linear models and artificial neural networks when complexity is considered as another managerial parameter. For that purpose, we have used the International Software Benchmarking Standards Group data set. The results obtained proved the benefits of integrating the complexity of the projects at hand into the models. They also addressed the need of a complex system, such as artificial neural networks, to capture the fine nuances of the complex systems to be modeled, the projects.     

The development of computer software for risk analysis: A decision support system development case study

Over the past eight years the Projects Department of BP's Group Engineering and Technical Centre has evolved a risk analysis methodology which is applied during the project appraisal phase to all major engineering construction projects. The computational methods in current use are based on the Common Interval and Memory (CIM) approach, which allows the direct enumeration of distribution combinations rather than the more common Monte Carlo simulation approach. Computer software has been developed in-house to apply these techniques. The programs are written in Fortran and are designed to be used interactively. This paper reviews the general framework of risk analysis applications on BP projects and the lessons learned in developing the first generation of computer software, used until 1985. Some of these lessons may be relevant to decision support system development by others. The development of a new generation of software, now implemented, is also discussed briefly.     

A Stochastic Model for Bidding

Competitive bidding situations involve considering a multiplicity of factors. Organizations must be able to weigh the relative probability of potential projects based on resource usage, project duration and competitor actions to decide which of many possible bids to submit. A bidding strategy designed to maximize expected long run return is crucial, since an organization can usually submit only one bid per project.This paper presents a family of stochastic dynamic programming models considering different bidding situations. Several projects, each with several potential bids, are available for each situation. The objective is to determine what bidding strategy will maximize expected returns. Models are developed for two principle bidding situations: sequential, where projects are bid individually; and simultaneous, where several projects are bid at one time. Next, the effects of over- or under-commitment of resources are incorporated into the models. Finally, changes in project timing and the resultant effects on bidding strategy are included.A numerical example traces the changes in bidding strategy which occur as the models are expanded. The general formulation of bidding problems is also discussed, including changing the bid success probabilities due to competitor actions, the possibility of crashing projects and alternate methods of performing projects.     

Learning from projects

The ‘learning organisation’ is frequently emphasised in the literature and in practice, and this is particularly important for project-oriented organisations. However, experience tells us that organisations tend not to learn adequately from project experiences. This paper reviews some of the work seeking to model and explain the behaviour of complex projects, which explains why lessons are difficult to learn from such projects—not the easy and obvious lessons but the lessons about complex non-intuitive project behaviours. From there it looks at why projects are frequently not reviewed, and seeks to offer practical proposals for carrying out reviews, using small models to enable lessons to be learned that provide understanding (rather than simply data), and distributing that learning around the organisation.     

The contribution of mathematical modelling to the practice of project management

This paper looks at the contribution that mathematical modellinghas made to project management over the past 50 years, and thecontribution it is currently making and can make in the future.Project Management started with well-defined foundations posingprecise, well-defined problems. In its growing phase, modellersplayed an essential role in taking the problems defined by theproject-management world and offering solutions, from the originalPERT, through resource allocation and levelling procedures,Monte Carlo simulation models, criticality analyses and so on.Since then, however, while the project management field itselfhas tried to establish its procedures, keeping to its philosophicalstance, much of the mathematical-modelling world has continuedalong its trajectory, producing ever more complex solutionsto ever more complex models, motivated by mathematical impressivenessrather than the need to solve real-world problems. This paperoutlines much of this work, some of which does find its wayinto project-network software but much of which languishes injournals. However, over the last decade or so, Operational Researchershave begun to build models of projects that are systemic anddynamic and explain many of the behaviours of projects thatconventional decomposition models do not; and at the same time,some of the Project Management world has started to realizethe limitations of its philosophical stance and started lookingto build new theory for modern, complex, dynamic projects. Asthese two trends come together, it is essential that modellersare at the forefront of building this new theory.     

DEMO: Towards a discipline of organisation engineering

Dynamic Essential Modelling of Organisation (DEMO) is a theory about the ‘construction’ and the ‘operation’ of organisations, that is rooted in the Communicative Action Paradigm regarding human communication and action. In this theory, the ‘working principle’ of an organisation consists of the entering into and the complying with commitments between human beings, where authority, responsibility and competence play an important role. The ‘construction’ of an organisation consists of a coherent whole of transactions, i.e., recurrent patterns of communication and action in which the commitments are entered into and complied with.DEMO is also a methodology for modelling, (re)designing and (re)engineering organisations based on that theory. Up to now some thirty projects have been carried out with DEMO. These projects are of very different kinds and they have been carried out in various types of organisations. The success factor has been the same for all these projects, namely the practical relevance of the concepts of DEMO, as well as their clear and precise definitions. Both managers and employees appear to be able to participate readily in identifying and understanding problems, and in generating appropriate and feasible solutions.     

几何分析中的基本概念与原理

本文是根据作者在中国科学院“中德几何分析伙伴小组”成立仪式上的演讲整理而成，主要目的在于通过回顾几何分析中的基本概念及基本定理，了解现阶段的研究情况和将来的研究线路，主要描述黎曼几何与量子场论中的思想，特别特别是极化物理量与几何量产生的变分问题。     

Structuring resource allocation decisions: A framework for building multi-criteria portfolio models with area-grouped options

Multi-criteria portfolio modelling has been extensively employed as an effective means to allocate scarce resources for investment in projects when considering costs, benefits and risks. Some of these modelling approaches allow the grouping of projects into organisational areas, thus also supporting the decision of resource allocation among organisational units in a way that is collectively efficient for the organisation. However, structuring in practice a portfolio model using this latter type of approach is not a trivial task. How should areas be defined? Where should new projects be included? How should one define the criteria to evaluate performance? As far as we know, there is very little indication in the operational research and decision sciences literatures on how to structure this type of model. This paper suggests different ways to structuring portfolio models where projects are divided into areas and evaluated by multiple criteria, and illustrates their use in two action-research projects. Drawing on these experiences it then suggests a general framework for the structuring of such models in practice. Directions for future research are also identified.     

Comparisons of models for estimation of safe doses using measures of the heaviness of tail of a distribution

Summary Procedures to estimate a dose of which the incidence probability is very small (e.g. 10⁻⁶) have been developed to evaluate the safety of chemical compounds. To compare models for estimation of safe doses quantitatively, a measure of the heaviness of tail of a distribution and a measure of tail at the origin are introduced. These measures have a theoretical basis for the comparison of tail behavior between distributions. Using the two measures, a tail ordering is defined to present a criterion for the comparison of models and is discussed for the probit, the logit, the Weibull, the (generalized) multihit, the (generalized) multitarget and the multistage models. The multistage model is most conservative among them, while the probit model has the reverse property. The Weibull model is more conservative than the logit. The multihit and multitarget models are found to be more sensitive than the Weibull and the logit. The Institute of Statistical Mathematics National Institute of Environmental Health Sciences     

<Emphasis Type="Italic">GEMINI-E3</Emphasis>, a general equilibrium model of international–national interactions between economy,energy and the environment

The purpose of this paper is to present the new version of GEMINI-E3, which is the fifth and incorporates significant changes from the previous version in particular with respect to its size and its modularity. GEMINI-E3 is a Computable General Equilibrium Model and represents now a family of models of different specifications and with several successive versions. It retains many specifications that are common to CGE models but also some specific features, mainly concerning the measurement and analysis of the welfare cost of policies and the great detail in the representation of taxation and social security contributions. The paper gives a detailed presentation of the model, its main blocks and equations, and shows how it can be adapted to specific contexts. In particular a new version is being developed jointly with the standard one, taking into account the constraints of the European Monetary Union and the unbalances in the labor markets of industrialized countries (GEMINI-EMU). This clearly shows that CGE models, beside their main virtue that is total consistency at the domestic and at the world levels, are very flexible in their specification.     

CFD modelling of thickeners at Worsley Alumina Pty Ltd

Computational fluid dynamics (CFD) modelling of process unit operations is a tool that is being used increasingly by mineral processing industries to reduce operating and capital costs and increase throughputs.Worsley Alumina first became involved with CFD modelling through support of the AMIRA Thickener Technology Project 266A in 1994, and subsequent extension projects in which CSIRO has been developing validated CFD models of thickener operation. The CSIRO Division of Minerals has been involved with CFD modelling since 1984 mainly on high temperature furnace applications and has been developing multi-phase thickener models since 1992. The benefits of obtaining a better understanding of flow patterns in thickeners using this modelling method became obvious and projects commenced in the third quarter of 1995 to utilise the CSIRO expertise. Projects have been ongoing almost continuously since that time. The CFD modelling was verified using tracers to measure actual flow patterns in a settler. Once verification had been achieved the CFD model was used to test innovative changes in design aimed at achieving higher throughputs and improved operation. These innovative changes when implemented on the full plant gave results similar to the CFD model predictions and resulted in improved process stabilisation, reduced chemical costs and very large savings in capital requirements for our major expansion that has just been completed. There are a number of assumptions made in the CFD model and these are discussed in detail in the paper together with details of individual CFD modelling projects and cost benefits achieved from completed projects.     

Using Infinite-server Resource Queue with Splitting of Requests for Modeling Two-channel Data Transmission

New Radio Access Technology 3GPP New Radio has become the fundamental wireless technology in the fifth-generation networks, which allows us to achieve high data rates due to the ability to work in the millimeter-wave band. But the key feature and the main problem of 5G New Radio networks is that people themselves, cars, buildings, etc. are signal blockers, while the base stations of the fourth generation networks have widescreen broadcasting and such small obstacles do not cause loss of connection. Service providers and mobile operators are already testing the proposed technology. In this connection, the scientific community has the task of analyzing the performance of these systems and increasing it in the future. Currently, there are known studies of “basic” mathematical models of such networks. By this term, we mean models built in the simplest possible assumptions. However, due to the justified necessity of introducing new technology into the daily lives of subscribers, service providers pose the scientific community with the task of analyzing the effectiveness of the most appropriate mathematical models. For example, a technology of splitting transmitted data into two streams using as 5G and both 4G transmission technologies is considered now by 3GPP Project Coordination Group. The paper is devoted to such a problem. We consider a mathematical model of the message transmitting with the implementation of the splitting function in the communication networks of New Radio technology in the form of a resource queueing system with a renewal arrival process and non-exponential service. For this problem, an approximation of a stationary two-dimensional probability distribution of the number of occupied resources in parallel service units is obtained. It is shown that this approximation coincides with the Gaussian distribution, and its area of applicability is shown.

     

Ergodicity of reversible reaction diffusion processes

Summary Reaction-diffusion processes were introduced by Nicolis and Prigogine, and Haken. Existence theorems have been established for most models, but not much is known about ergodic properties. In this paper we study a class of models which have a reversible measure. We show that the stationary distribution is unique and is the limit starting from any initial distribution.The work was begun while the first author was visiting Cornell and supported by the Chinese government. The initial results (for Schlögl's first model) was generalized while the three authors were visiting the Nankai Institute for Mathematics, Tianjin, People's Republic of ChinaPartially supported by the National Science Foundation and the Army Research Office through the Mathematical Sciences Institute at Cornell UniversityPartially supported by NSF grant DMS 86-01800     

A method for determining the equilibrium states of dynamic systems

A heuristic method is presented for determining the equilibrium states of motion of dynamic systems, in particular, spacecraft. The method can also be applied to the solution of sets of linear or nonlinear algebraic equations. A positive-semidefinite functional is formed to convert the problem to that of finding those minimum points where the functional vanishes. The process is initiated within a selecteddomain of interest by random search; convergence to a minimum is obtained by a modified Davidon's deflected gradient technique. To render this approach feasible in the presence of constraints, the functional is modified to include penalty terms which cause the functional to approach infinity at the constraint boundaries. Close approximations to solutions near the constraint boundaries are found by applying Carroll's approach in successively reducing the weighting factors of the penalty terms. After finding a minimum, the local domain around this point is eliminated by adding to the functional an interior constraint term, representing the surface under a hypersphere centered at the minimum point. The domain of consideration now becomes the subdomain formed by subtracting the space contained within this hypersphere from the previous domain of interest. Minima are now sought within the remaining space, as before.This paper is derived from research performed by the author while employed by TRW Systems Group, Redondo Beach, California.The author acknowledges the helpful suggestions of Dr. G. Bekey, University of Southern California, and those of Mr. E. A. Quast, Dr. M. P. Scher, and Dr. R. J. Wiley, Dynamics Department, TRW Systems Group, Redondo Beach, California.     

PPP项目国有企业隧道行为研究

PPP项目中, 国有企业时常利用控制权优势和信息不对称实施隧道行为, 加大了民营资本进入PPP项目的阻力, 损害了项目整体利益, 不利于PPP模式的健康可持续发展。本文在分析PPP项目中国企隧道行为表现形式和形成机理的基础上, 分别通过博弈论和投资组合模型构建了隧道行为实施条件和发生概率模型。研究结果表明, 国企实施隧道行为需具备基于控制权的先决条件, 挖掘成本相对项目利益的比重越大, 所需控制权越高; 而隧道行为的发生概率随着挖掘成本的降低和控制权的增加而增加。通过蒙特卡洛模拟对河北承德市双峰寺水库PPP项目进行案例分析, 验证了国企隧道行为实施条件和概率模型的可行性和适用性。最终, 分别从提高民企的谈判能力, 增加PPP项目信息透明度, 加强政府监管, 并使国企和项目整体产生利益协同四个方面提出隧道行为治理机制, 保障PPP模式的可持续发展。     

The initiation,evaluation and selection of operational research projects

This paper discusses the problems involved in conducting successful Operational Research within a large organisation and suggests ways of overcoming them. It describes ways in which Operational Research projects arise, methods of assessing their relative merits, and methods used by the authors to obtain a suitable portfolio of projects. It is argued that an Operational Research Group should apply to its own project planning the scientific approach that it advocates for others.     

Data Envelopment Analysis in the Presence of Both Quantitative and Qualitative Factors

This paper presents a framework for incorporating ordinal data factors into the standard ratio DEA model. An application involving the prioritization of R&D projects is presented as a case in point where such ordinal factors appear in a natural way. Two different models for incorporating ordinal data are developed; one in which the ordinal factors are ranked and one where they are not. Finally, the issue of selecting a lower bound ? on factors is addressed.     

Cylindrical reinforced shells most stable under multilateral external pressure

Rational parameters are selected for reinforcing a cylindrical shell, which is externally loaded on all sides, in which the upper critical loading achieves the maximum value. Determinations are made of the appropriate region of application of the solution discovered for all elastic elements of the composition, and also indications given of the possibility of constructing other projects which in the specified concept can be considered rational.Institute of Hydrodynamics, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Mekhanika Polimerov, No. 1, pp. 75–83, January–February, 1975.     

Developing a Systems Approach to the Problems of Industry — Lessons Based on Experience at IIASA

This paper describes progress on a number of research projects initiated in the Management and Technology Area of the International Institute of Applied Systems Analysis in the period 1977/80. The projects were undertaken by an international, multi-disciplinary, team concerned with the study of management problems arising from technological change. The experience obtained is used to explore the need for, and feasibility of, undertaking such problem-oriented programme research at the national level. It is concluded that the need to conduct methodological research of this nature is great, though not always self-evident; that the financial and organisational problems would be severe, though not insuperable; and that it is time for practising operational researchers and applied systems analysts to flex their muscles to this end.