bluuebunny/crossref_metadata_2025 huggingface dataset:
Exponential Fitting of Suicide Rate and National Intelligence Estimates
Authors: Voracek Martin
Published: June 2007

Positive ecological (group-level) associations of Lynn and Vanhanen's 2002 national intelligence (IQ) estimates with the suicide rates of men and women across 85 countries and with the suicide rates of the male, female, and total elderly population across 48 Eurasian countries reported recently is extended by the finding that this ecological association was notedly better accounted for by exponential fitting than by linear fitting. This evidence implies that the effect of a shift in the national IQ on the suicide rate is proportional, not absolute. As a rule of thumb, a 5-point shift in national IQ roughly corresponds to a 50% change in the national suicide rate.
Type of Motion in Inverted Self-Motion Perception Induced by a Foreground Stimulus
Authors: Nakamura Shinji
Published: June 2007

Slowly moving foreground induces an illusory self-motion perception in the same direction as its motion direction (inverted vection). In this study, the effects of motion type of the foreground stimulus on inverted vection were investigated using a sample of 3 men and 1 woman. As indices of perceived strength of the inverted vection, duration and estimated magnitude were measured. Analysis of the psychophysical experiment indicated that a translating foreground induced inverted linear vection in the same direction as the stimulus motion. However, a rotating foreground did not induce an inverted roll vection. Statistical analyses indicate that there is a significant difference between two foreground motion conditions (Duration: t3 = 14.54, p < .01; Estimation: t3 = 16.92, p < .01). This result supports the hypothesis that eye-movement information is responsible for the occurrence of inverted vection.
The Historical Reconstruction of Knowledge About Race: Implications for Transformative Teaching
Authors: Banks James A.
Published: June 2007

I contend that knowledge reflects both the reality observed as well as the subjectivity of the knower. The attempt to clearly distinguish the objective and subjective elements of knowledge, a key feature of mainstream Anglo-American epistemology, is inconsistent with the ways that human beings know. I use a historical case study of the construction and reconstruction of race between the late 19th century and the 1940s to document the ways in which the social, cultural, political, and historical contexts in which knowers are embedded influence the knowledge they construct and reconstruct. The final part of this article discusses the implications of the historical construction of race for transformative classroom teaching.
How probable is probable? A numerical translation of verbal probability expressions
Authors: Beyth‐Marom Ruth
Published: July 2007

The reported experiment took place in a professional forecasting organization accustomed to giving verbal probability assessments (‘likely’, ‘probable’, etc.). It attempts to highlight the communication problems caused by verbal probability expressions and to offer possible solutions that are compatible with the forecasters overall perspective on their jobs

Experts in the organization were first asked to give a numerical translation to 30 different verbal probability expressions most of which were taken from the organization's own published political forecasts. In a second part of the experiment the experts were given 15 paragraphs selected from the organization's political publications each of which contained at least one verbal expression of probability. Subjects were again asked to give a numerical translation to each verbal probability expression

The results indicate that (a) there is a high variability in the interpretation of verbal probability expressions and (b) the variability is even higher in context. Possible reasons for the context effect are discussed and practical implications are suggested.
Short‐run macroeconomic forecasting: The OECD performance
Authors: Smyth David J.
Published: July 2007

Forecasts for the seven major industrial countries, Canada, France, Germany, Italy, Japan, the United Kingdom and the United States, are published on a regular basis in the OECD's Economic Outlook. This paper analyses the accuracy of the OECD annual forecasts of output and price changes and of the current balance in the balance of payments. As a reference basis, the forecasts are compared with those generated by a naive model, a random walk process. The measures of forecasting accuracy used are the mean‐absolute error, the root‐mean‐square error, the median‐absolute error, and Theil's inequality coefficient. The OECD forecasts of real GNP changes are significantly superior to those generated by the random walk process; however, the OECD price and current balance forecasts are not significantly more accurate than those obtained from the naive model. The OECD's forecasting performance has neither improved nor deteriorated over time.
Strategic issues in development management: Learning from successful experience. Part II
Authors: Conyers Diana , Kaul Mohan
Published: July 2007

Part I of this paper, published in Vol. 10, no. 2, dealt with the choice of criteria for determining the success of local development initiatives. Part II looks at the broader implications of the factors contributing to success in the local, national and international contexts. The majority of local initiatives require external assistance. Six major issues are discussed: the qualities which external agencies need in order to provide effective support; the relative merits of governmental and non‐governmental organizations; the different levels of NGO operations; relations between governments and NGOs; North‐South collaboration; and training implications.
Hershey Foods, cocoa, and Belize: A collaborative model for third world development
Authors: Gaarder Robert , McCommon Carolyn
Published: July 2007

The following article describes a rare case of a U.S. multinational collaborating with the public sector on an economic development project. The project took place in Belize and directly addressed the development priorities of this Central American country. From 1984 until 1987, Hershey Foods Corporation was a co‐operative partner with the Belizean Ministry of Agriculture in the Belize Accelerated Cocoa Production Project aimed at introducing the latest cocoa production methods to local farmers. Other key participants in the project included the development arm of the United States Government—the Agency for International Development—and two private voluntary organizations: the Pan American Development Foundation and Volunteers in Technical Assistance. This article presents the case for more configurations like this one in future development projects. The article is divided into the following sections: the need for a private sector role in development, background on the Belize case, a model for developing collaborative relationships, and the benefits received by the partners as a result of their collaboration on this project.
Experience of training for decentralized planning in Nepal
Authors: Poudyal Lokendra Prasad
Published: July 2007

People's participation is both a method and an objective of rural development programmes in Nepal. The government has adopted decentralization measures to facilitate this. As the subject of decentralization involves new roles and responsibilities for both people and government officials, designing viable training programmes has been emphasized. Commensurate with this, a pilot training programme has been conducted in the Tanahun District for two years. The objective of this programme was to produce a decentralized planning training module which could be replicated elsewhere. This paper deals with the content of this programme and highlights the lessons learnt.
Institutional analysis and decentralization: Developing an analytical framework for effective third world administrative reform
Authors: Wunsch James S.
Published: July 2007

As we enter the 1990s, scholars and practitioners of development administration in the Third World share a deep concern with its disappointing performance. Looked to as the primary agent of modernization during the optimistic first days of independence, many now blame it for the development stagnation of much of the Third World over the past two decades. Reinforced by the events of 1989 in Eastern Europe, calls for privatization and radical cutbacks in the state are increasing. Indeed, while the causes of Third World development stagnation are undoubtedly multiple and diverse, it is difficult to refute the charge that the hierarchical, bureaucratic, centrally‐led strategy has not achieved what was expected of it. The question which faces responsible and concerned scholars, practitioners and officials today, is what can and should be done about all this? This paper recommends avoiding grand and precipitous changes in organizational strategies: indiscriminate privatization and dismantling the state, it argues, would be just as much an error as the earlier whole‐cloth commitment to centralist‐bureaucratic organization. Instead it argues that theoretical and analytical tools effective in making more subtle and refined choices among institutional alternatives must be developed. It presents a preliminary analysis of one strategy which might offer this, and illustrates how it can be used to design organizations more likely successfully to deliver services and sustain investments in the Third World.
The state of training in public policy management in Ghana
Authors: Dotse F. Mawuena
Published: July 2007

This paper discusses the relevance and state of training in public policy management in Ghana. The author argues that the lack of an institutional base for policy analysis is evident in the abdication and paralysis of policy‐making, as well as the inability of the management development institutions to institutionalize training programmes in public policy management. Recognizing politicians and bureaucrats as complementary actors in the policy process, it is argued that organizing training programmes for them could contribute to improved policy‐making. The content, methodology, duration, target group and impact of current training programmes in public policy management are analysed. Although the dearth of relevant local reading material on policy issue is identified as a problem in the teaching of public policy in Ghana, reference is made to some available publications on local public policy issues which could supplement Western‐biased reading materials. Other problems discussed are the heterogeneous background of course participants and the non‐involvement of faculty members in policy making. The paper concludes with recommendations on policy preview workshops; seminars for politicians and senior bureaucrats; development of policy analysts; and complementarity among the local management development institutions.
Cities and people: Towards a gender‐aware urban planning process?
Authors: Rakodi Carole
Published: July 2007

Recognition of the deficiencies of traditional ‘blueprint’ approaches to land use and infrastructure planning has led to increased emphasis on management of the process of urban development. Such management should recognize the distributional impacts of decision‐making and be responsive to the needs of residents. However, much urban planning activity has been and continues to be gender‐blind. In order to redress this deficiency, it is argued that increased understanding is needed of women's economic and social roles in urban society, their exclusion from economic opportunities and decision‐making processes, and the discriminatory nature of much legislation. Urban residents’ experience is shaped both by household strategies and by the way in which they are affected by or can affect planning, investment and management decisions made at the neighbourhood or city level. Differing experiences may be related to class and ethnicity, but are also likely to be gender‐specific. The potential impact of policy and investment in a variety of sectors of urban development on residents, especially women, is explored. Recommendations are made for a more gender‐aware approach to planning for economic activity, land and shelter, public transport and infrastructural and social services, and for specific actions to be taken by both planners and residents.
Patrimonial economics and informal bureaucracies: Public administration and social reality in the least developed countries of the 1990s: A review article
Authors: Garvey Brian
Published: July 2007

Commentators in many poorer countries, examining the political realities of the Third World from within new and interesting micro‐economic perspectives, have rediscovered the relevance of dysfunctions in government as pointers to the true nature of state relations and economic development. The result has been the appearance of a literature on two commonly observed phenomena in the least developed countries of Africa, South Asia and Latin America: the enhanced economic role of ‘second’ or ‘informal’ economies, and the declining relevance of formal state structures which results partly from economic incapacity. This paper surveys some of the more significant recent examples of this literary output and relates their findings to the problems of public administration in those countries which experience or are likely to experience these phenomena.
Urban local government finance in Nigeria: The case of Lagos municipal area
Authors: Olowu Dele
Published: July 2007

One of the most important results of the global reform of local governments in Nigeria in 1976 was to initiate a progressive increase in the amount of monetary transfers to local governments (LGs) by federal and state governments (especially the former). The proportion of federally collected revenues devoted to LGs increased rapidly from less than 2 per cent in 1976 to 15 per cent in 1990. This has enabled Nigerian LGs to play a more visible role in total public expenditures. On the other hand, huge federal transfers have led to sharp declines in absolute and relative terms in locally generated revenues. The two Lagos municipalities are able to generate up to 50 per cent of their total revenues. In contrast, the average for all local governments in the country is 4–5 per cent. The relatively large internal revenue sources in the two Lagos municipalities results in generous surpluses, which they are able to channel into capital development or special project expenditures. The single most important internal revenue source is the property tax, which is not even collected in some other large cities, such as Kano, Ogbomosho and Sokoto.
Rural local government finance in Zimbabwe: The case of Gokwe District Council
Authors: Mutizwa‐Mangiza N. D.
Published: July 2007

In spite of the many problems inherited at independence in 1980, rural local government in Zimbabwe is, in comparison with many other countries in the region, fairly robust and well organized. This paper examines the Gokwe District Council, one of the more dynamic and potentially very prosperous rural local authorities in the country. The case study shows that the achievements of the council can be explained not only in terms of factors internal to the district, but also in terms of the overall system of local government and finance in Zimbabwe.
Local management of aid‐funded projects
Authors: Maddock Nicholas
Published: July 2007

Local management means giving responsibility for the implementation and management of development projects to people and institutions in the recipient country. The main arguments for local management are that it offers the potential to increase the responsibility and accountability of national institutions and should help to build a cadre of experienced local project managers. These are all important contributions to sustainable development. There are, however, some constraints on the effectiveness of local management, including the limited supply of good managers and the difficulty of ensuring adherence by those implementing projects to donors' procedures and regulations. The role of donor agencies under local management is yet to be clearly defined. Donor agencies will face difficult professional judgments on whether, when and how to intervene where projects are not being competently managed by national institutions.
Public enterprise reform: Managerial autonomy, accountability and performance contracts
Authors: Islam Nasir
Published: July 2007

The underlying assumption in this paper is that autonomy and accountability are both fundamental prerequisites for the effective functioning of state‐owned enterprises. The paper first examines the traditional, dichotomous approach to the autonomy‐accountability conundrum. This approach posits the relationship as process oriented, pervasive, quantitative and based ona prioricontrols. A more recent view of control and accountability asa posteriori, qualitative, strategic, results‐oriented and non‐zero sum is then briefly analysed. The paper presents a review of the theory and practice of performance contracts (PC) as tools to implement the latter approach. Three basic models of PCs—Senegal'scontratplan, Pakistan's signalling system and India's memorandum of understanding—have been analysed, comparing the negotiating process, major players, substantive elements and results. Thecontratplan is more of a legal document, at least in formal terms, than the other two. None of the three models, however, provides any sanctions in case of a violation of the contract by the governments. Although the Indian and Pakistani PCs appeared to be more successful than the Senegalese contracts, the relationship between financial performance and performance contracts remains far from conclusive. In all the three countries, the contracts have failed to provide a single window through which government‐enterprise interface can be effectively managed. Thus the problem of multiple principals and single agents remains unresolved.
Managing research institutions in developing countries: Test of a model
Authors: Kiggundu Moses N.
Published: July 2007

This article proposes a model for the analysis, management and development of research institutes in developing countries which incorporates four interdependent dimensions: (i) a strategic management dimension concerned with the management of the organisation's internal and external environments and their interrelationships; (ii) a dimension concerned with ‘collaborative institutional arrangements’; (iii) an internal management and supervision dimension; and (iv) a ‘research operations’ dimension. A preliminary corroboration of the model's validity is derived from a review of relevant published literature and summaries of evaluation studies of research institutions in developing countries.
Managing equity and gender in an agricultural programme in Malawi
Authors: Hirschmann David
Published: July 2007

The challenge of introducing greater equity into a society as unequal and as poor as Malawi's has become is a daunting one. It involves nothing less than attempting to commence the reversal of a historic process that originates in the colonial system of production and has continued, even intensified, during three decades of political independence. In that process a very small elite arrogated all of the major components of political power and economic privilege. Attempting to restore, even to a limited degree, fairness in the distribution of assets and opportunities to such a society involves numerous, complex, and sometimes contradictory, sets of questions and responses. It also requires an unpackaging of the notion of ‘equity’ and the category of‘women’. This article sets out to explore some of those questions from a management perspective. First, in order to demonstrate the complexity and scale of the problem, as well as the limits of this particular experiment with reform, it will provide a brief historic background to the present structure and dynamic of Malawian agriculture. Second, it will, even more briefly, explain US AID's Agricultural Sector Assistance Programme (ASAP), which sought to alter in a modest way some of the major elements of agricultural inequity in Malawi. Third, it will analyse some of the procedural and management dilemmas confronting the programme. And, finally, it will set out some principles for responding to these management problems.
Personnel practices in careers of women at the top in government and business in Nicaragua and Costa Rica
Authors: Snyder Monteze M. , Osland Joyce , Hunter Leslie
Published: July 2007

This article, which is the first empirical study of upper‐level female managers in Central America, extends the exploration of similarities and differences between public and private sectors in human resource management to the context of developing countries. A comparison of work hours, recruitment and selection practices, mentoring, political pressure, gender discrimination and sexual harassment, reported by female managers in public and private organizations in Nicaragua and Costa Rica, yielded no sector‐based differences and few country‐based differences. We conclude, therefore, that the public sector is not a more supportive or more fair employer for women in management than the private sector in these two countries, contrary to the assumption in the women‐in‐management literature that the public sector is a more hospitable environment. Improvements in human resources practices are appropriate in both sectors.
An Operator Method for the Addition of Two Angular Momenta by Symmetrizing the Product of n Spin Functions
Authors: Ansari S. M. Razaullah
Published: July 2007

A general expression of Clebsch‐Gordan coefficients is derived by means of de Broglie‐like méthode de fusion: the second angular momentum is added to the first in n steps of half each, the maximum symmetric composition of the n spin functions being taken into account explicitly. The procedure is operatorial.

Group‐theoretically speaking the irreducible representations of the direct product of two irreducible representations of the rotation group are realized via symmetric group Sn with the aid of projection operators (equivalent to Young's symmetrizers). The decomposition of the representations of Sn therein is performed inductively by utilizing the chain of subgroups: Sn ⊃ Sn−1 … ⊃ S2 ⊃ S1.
Beam Optics and Particle Transport
Authors: Skarek Paul
Published: July 2007

Methods and results of beam optics with respect to the transport of charged particle beams in experiments on high energy accelerators are reviewed.
Recent Applications of KN Forward Dispersion Relations and Sum Rules
Authors: Queen N. M. , Restignoli M. , Violini G.
Published: July 2007

Recent applications of kaon‐nucleon forward dispersion relations, superconvergence relations, finite energy sum rules, derivative sum rules, and the Adler‐Weisberger sum rule are reviewed. These dispersion relations and sum rules have been used for the determination of the KNA and KN coupling constants, the phases of the kaon‐nucleon forward scattering amplitudes, and the Regge pole parameters, and have allowed tests of the PCAC hypothesis for strangeness‐changing currents. They also provide important constraints which help to resolve ambiguities in the phenomenological analysis of the scattering data. A critical comparison of various methods which have been proposed is given, the theoretical predictions are compared with experiment when possible, and our present knowledge of the kaon‐nucleon interaction parameters is summarized. Some new results are presented.
Further Evidence against the Possibility of Faster‐than‐Light Particles
Authors: Strnad J.
Published: July 2007

Arguments are added to the growing number of arguments against the possibility of faster‐than‐light particles. Causal loops with faster‐than‐light particles are discussed in the framework of non‐quantum special relativity. Thought experiments with steady currents of faster‐than‐light particles show that the reinterpretation principle is incompatible with the causality principle. If both principles are used consequently paradoxial situations arise. These are visualized utilizing Brehme diagrams. The final conclusion is that particles cannot travel on a macroscopic scale faster than light if space and time are homogeneous and if the relativity and causality principles are valid.
Application of Partial Wave Crossing Relations to πN Scattering
Authors: Jakob H.‐P. , Krubasik E. , Steiner F.
Published: July 2007

The partial wave crossing relations derived in a recent paper by Steiner [1] are used for a calculation of the πN S‐wave amplitudes in the region 8 ≦ s ≦ (M − 1)2. The corresponding Argand diagrams show the pseudoresonance behaviour predicted in [1]. The results for the real parts are compared with an independent calculation using fixed‐t dispersion relations.
On the Connection between Particles and Poles of the S‐Matrix
Authors: Fonda L.
Published: July 2007

In axiomatic S‐matrix theory it is usually assumed that stable particles give rise to simple poles of the S‐matrix for real negative energies while unstable particles give rise to poles close to the real axis on an unphysical sheet of the energy Riemann surface. The stable particle — pole association has been known for a long time not to be always true. For example in potential scattering what is relevant in this case in fact is not the S‐matrix but the Jost function. The zeroes of this function for real negative energies are in fact in one‐to‐one correspondence with the bound states, while the correspondence may break down for the poles of the S‐matrix. On the other hand it has recently been pointed out that there also is in general no connection between unstable particles and poles of the S‐matrix.
Unified Free Quantum Fields for Massive and for Massless Particles
Authors: Mutze U.
Published: July 2007

For any mass m ≧ 0 and arbitrary spin, free relativistic quantum fields are constructed using the same formulas for m > 0 and for m = 0. The transformation properties of these fields under P, C, T and some questions concerning super‐selection rules are discussed.
Properties of Equilibrium States on Quasilocal C⋆‐algebras
Authors: Andersson Stig I.
Published: July 2007

These notes have grown out of a seminar series and are to a large extent of a review character (this goes especially for section 3).

Novel aspects are indicated in connection with the continuous point particle systems and the relations between equilibrium conditions. We concentrate on some less often treated subjects, viz. the decomposition theory and equivalence of the equilibrium conditions.
Weak Neutrino‐Lepton Annihilation into Hadrons
Authors: Actor Alfred
Published: July 2007

An exploratory study of weak neutrino‐lepton annihilation into hadrons, v̄l + l → hadrons is presented. Simple cross‐section estimates indicate processes of this type may be observable in a large bubble chamber. We discuss the information one could hope to obtain from such experiments. General formulas for amplitudes and cross sections are given for v̄l + l → hadrons assuming a point‐like V – A interaction. To establish tests of the V – A interaction, we recalculate the annihilation amplitudes assuming a point‐like scalar‐pseudoscalar or tensor‐pseudotensor interaction. The extension to theories with intermediate vector bosons is sketched. We discuss the connection between v̄l + l → hadrons and e+e− → hadrons implied by the conserved vector current hypothesis. We note that in v̄l + l → rH, K⋆(890), A1, B creation (these reactions enjoy comparatively large cross sections) the leptonic as well as hadronic couplings of these J = 1, I = 1/2 or 1 mesons could be determined. A related possibility is the direct creation of new heavy charged J = 1 mesons. The normal J = 1 resonance region could be explored with neutrino energies of the order 500–2000 GeV. For this, and for higher‐energy work, a TeV proton accelerator is clearly necessary.
A Jet Model Study of Correlations in Hadron‐Hadron Reactions Due to Resonance Production
Authors: Biebl K. J. , Klein M. , Nahnhauer R.
Published: July 2007

Secondary particle correlations are discussed as a basic feature of hadron induced multiparticle reactions in the 5 to 1500 GeV energy range.

Two introductory sections are devoted to definitions of cross sections and to empirical regularities of multiple production. Many of these regularities can be understood to be consequences of energy‐momentum conservation and limited transverse momenta (uncorrelated jet model (UJM)). An extension of the UJM is considered, the correlated jet model (CJM), by introducing dynamical short range correlations between the particles which are assumed to be due to resonance production. Many properties of single‐particle distributions and correlation functions can be derived already from kinematics of resonance decay. The CJM is used to investigate in detail the origin of angular correlations (azimuthal, GGLP‐effect) and of correlations between neutral and charged particles (〈π°〉nc, f00(nc)). These correlations are shown to arise almost completely from the production and decay of mainly two‐particle resonances like ∂°, K* and Δ, the main evidence coming from the use of the invariant mass as the basic variable where only resonances or reflections of them give remarkable effects. Compared to the UJM, the CJM is the first approximation of a successive correlations analysis of the production amplitude squared, i.e. having separated the effects of energy‐momentum and quantum number conservation. This might be also interesting in view of the forthcoming accelerator generation.
First Quantum Corrections to the Classical Partition Function for a Non‐Relativistic Electrodynamical System
Authors: Ruiz F. Ruiz , Alvarez‐Estrada R. F.
Published: July 2007

The classical partition function for a system in thermodynamical equilibrium formed by N identical non‐relativistic particles interacting through Coulomb potentials and with the dynamical electromagnetic field is studied. It is proved that the dynamical or transverse EM degrees of freedom decouple from the particle ones. It is also shown that this decoupling does to take place in the quantum mechanical partition function. The leading quantum corrections to the classical partition function are explicitly given. Such corrections are shown to be determined by instantaneous dipole‐dipole coulombic interactions and by self‐energy effects, and to receive no contribution from the interaction among different particles mediated by the dynamical EM field.
Brans‐Dicke Cosmology with a Scalar Field Dependent Cosmological Term
Authors: Bertolami Orfeu
Published: July 2007

We propose a cosmology based on the Brans‐Dicke theory with a cosmological term dependent in the scalar field. It is shown the existence of a solution in a Robertson‐Walker metric that does not suffer from any unnatural fine tuning in the very early Universe such as the horizon, homogeneity, isotropy and flatness problems and does not present any difficulty concerning the GUTs magnetic monopoles.
Variation of defect density and its influence on yield extrapolation for integrated circuits
Authors: Kleppmann W. G. , Vollertsen R.‐P.
Published: July 2007

Using the example of stress tests for dielectric breakdown, the close relation between the local variation of defect density on the one hand and the area dependence of yield is verified directly.

There is appreciable real variation of defect density (in addition to purely statistical fluctuation) even within individual wafers, but also additional variation between wafers processed together in groups and further variation again between groups of wafers processed separately. Correspondingly, the dependence of yield on area differs progressively more from the Poisson model as more (different) data are summarized in a single average yield.

The local variation of defect density also depends on stress level, and hence on the defect considered.
Micro and macro analysis of a thermonuclear fusion plant for reliability and performance
Authors: Chaharbaghi Kazem , Buende Rolf
Published: July 2007

The Next European Torus (NET) must be operated with appropriate reliability and availability levels if it is to attain its targets. A basic simulation model, the principles and potentials of which had been previously demonstrated, has been considerably extended to provide a more accurate representation of the operations of NET and to facilitate its study under various operating and reliability considerations. The latest simulation model of NET incorporates the physics phase as well as the technology phase. It encompasses complex features such as time and event dependent failure rates and independent failures. For ease of manipulating the uncertainties associated with the reliability data, the model has been furnished with the normal, exponential, lognormal and Weibull distribution modules. The level of subsystem breakdown is easily adjustable to match the needs of the design that is growing in detail. A goal‐seeking procedure has been developed for use in conjunction with the simulation model. The application of this procedure culminates in operating and reliability strategies which will enable NET to achieve its intended targets. This paper describes the operating and reliability features of NET together with the ways in which they have been captured by the NET simulation model. The underlying philosophy and application of the goal seeking procedure is also demonstrated through illustrative results.
Fault curves—A novel drift‐fault diagnosing method for condition monitoring
Authors: Drake P. R. , Williams J. H.
Published: July 2007

A drift‐fault diagnosing method is presented based on fault curves fitted to changes in a single characteristic of a system performance curve such as the peak of the step response. The method consists of fitting a fault curve, for each potential fault in the system, to samples of the characteristic produced under different levels of the faults. Unknown faults are then diagnosed, irrespective of severity, by seeing which fault curve is closest to the characteristic produced by the system under test. It is argued that this method is very appropriate for diagnosing faults detected by condition monitoring systems since these will be drift faults, and because the method can be applied to normal operational signals without the need to inject special test signals.
The use of computer‐aided engineering in reliability studies
Authors: Watts Gareth
Published: July 2007

This paper discusses how computer‐aided engineering can be extended beyond the use of design verification into the area of dynamic failure effects analysis for both digital and analogue electronic circuits as well as complete systems encompassing any engineering discipline.
Evolution of VLSI reliability engineering
Authors: Crook D. L.
Published: July 2007

Projection indicates that by the turn of the century microcomputer chips will have 100 million transistors and failure rates of less than 10 FIT. Traditional accelerated product life tests and wafer level reliability measurement techniques being developed at present will have severe limitations in resolving the 10 FIT failure rate of complex VLSI circuits. This paper discusses these limitations along with the change in direction that the reliability engineering and manufacturing community will have to take over the next decade to meet the challenge of continuously decreasing failure rate goals.
Reliability of multi‐channel Ga1−xAlxas high electron mobility transistor (HEMT) integrated circuits
Authors: Christou A. , Tseng Wen
Published: July 2007

The reliability of HEMT ICs has been analysed when they are treated as weakly coupled dual channel systems. The separation distance between the two‐dimensional electron gas channels is the critical parameter which affects reliability. The introduction of deep traps at 0·65 eV has been shown to occur during accelerated life tests. In addition, the HEMT dual channel IC reliability results tend to follow the enhancement mode degradation statistics. All testing was carried out at 12 GHz and at channel temperatures between 130°C and 250°C.
Convenient construction of t‐tests for quality evaluation
Authors: Nachlas Joel A.
Published: July 2007

An available numerical approximation to the Student's t distribution is described and its use in the construction of t‐tests is presented. The result is a convenient and accurate computer based approach to the selection of the sample size and critical value to be used in a t‐test. Computational logic for implementation of the approach is provided and the method is illustrated by an example.
Control chart design a review of standard practice
Authors: Porter Leslie J. , Caulcutt Roland
Published: July 2007

Many standard texts on SPC offer simple procedures for setting up control charts. Although the procedures work well in some situations, there are many instances where the procedures do not produce useful charts. The failure to sustain SPC initiatives is often due to an over simplistic model of process variability.

This paper examines the widely used procedures for setting up control charts and illustrates how these may fail when the process variability has certain characteristics. A more robust alternative procedure is examined in some detail. This involves taking a closer look at process variability and incorporating this with control chart design.
Testing for reliability improvement or deterioration in repairable systems
Authors: de La Mare R. F.
Published: July 2007

This paper reviews the derivation and application of the reverse arrangement test which is used to assess whether a system has improved or deteriorated in a reliability sense. Because the well‐known and published table of statistics for this test is erroneous, the prime objective of this paper is to provide the correct statistical table. A secondary aim, however, is to demonstrate how this table can be applied when there is a paucity of failure data for each individual system and to show how a more meaningful reliability assessment can be obtained by pooling results, from the reverse arrangement test, for several systems.
Floating gate memories reliability
Authors: Crisenza G. , Clementi C. , Ghidini G. , Tosi M.
Published: July 2007

Besides conventional IC failure mechanisms, the floating gate (FG) device reliability is affected by data retention, characteristic of non‐volatile memories, and endurance, typical of electrically erasable arrays.

The subjects of this work are EPROM and flash EEPROM, the leading and most promising devices among the FG non‐volatile memories.

The degradation mechanisms observed in programming and erasing steps are investigated. EPROM data retention is associated with intrinsic and defect related charge loss with both electronic and ionic processes involved. Experimental results are presented.

The reliability problems associated with repeated write/erase cycles are introduced, and their effects on EEPROM endurance discussed.

Finally, a fishbone diagram for data retention is proposed. The complexity of technology and the cell scaling down with increasing chip size impose lower failure rate goals and reliability becomes integrated within the manufacturing process.
Emission microscopy
Authors: Kölzer J. , Dallmann A. , Deboy G. , Otto J. , Weinmann D.
Published: July 2007

Emission microscopy has now become established as an effective technique in terms of reliability physics of industrial semiconductors. This convenient method allows chip verification and failure analysis to be carried out in many applications. Besides this, emission microscopy provides a technique for use in device engineering and the optimization of test structures. The key to using this technique to permit a more sophisticated quantitative analysis lies in an unique assignment of the light emission to the defect mechanism. Since the corresponding phenomena are numerous and their details have to be clarified before this technique can be used routinely in a quantitative rather than qualitative approach, fundamental investigations were carried out on the basis of test structures. The applicability of quantitative aspects of emission microscopy in practice, i.e. exemplified by some relevant case studies, has further been discussed in this paper.
Transiently triggered latch‐up in cmos twin‐tub and epitaxial technologies
Authors: Pavan Paolo , Caprara Paolo , Stucchi Michele , Zanoni Enrico
Published: July 2007

We present in this work an analysis of transiently triggered latch‐up in test‐structures fabricated using a twin‐tub process implemented on two different substrates: a p‐type and a p p+ epitaxial one. Steady‐state electrical characterization confirmed the well‐known increased latch‐up resistance of epitaxial structures with respect to standard ones. In this paper it is shown that, depending on the chosen electrical configuration, when latch‐up is transiently triggered, epitaxial structures may have dynamic triggering currents lower than twin‐tub ones. The influence of some layout variables on turn‐on threshold voltage has been investigated for all samples.
A structural reliability model for composite materials
Authors: Corvi Andrea , Vangi Dario
Published: July 2007

This work is a part of a project aimed at developing a model and procedure to evaluate the structural reliability of a laminate whose laminae properties are statistically known. The inputs consist of the laminae's elastic properties (deterministic in that they are not as closely related to manufacturing technology) and the derived allowable strengths (aleatoric variables), as well as the sequence (number, orientation, position) of the laminae in the laminate. The output, the laminate's structural reliability, allows determination of the laminate's collapse process, with the most probable lamina failure sequence.
Supply current monitoring in cmos circuits for reliability prediction and test
Authors: Richardson A. M. , Dorey A. P.
Published: July 2007

The monitoring of supply current in CMOS VLSI devices has been suggested as a tool for both detecting reliability hazards and increasing the effectiveness of standard functional testing. This paper reviews these techniques and describes a method used at Lancaster for evaluating the IDDQ test.
An application of a bathtub failure model to imperfectly repaired systems data
Authors: Love C. E. , Guo R.
Published: July 2007

In this paper we use an exponential power distribution to develop a bathtub failure model for repairable systems. These results are compared with those using the more familiar Weibull distribution. The analysis is extended to three types of repair scenarios: good‐as‐new repairs (in which the repair following a failure completely refreshes the failure intensity), bad‐as‐old repairs (in which the repair has no effect on the failure intensity) and imperfect repairs (in which the failure intensity is only partially reset). We apply this analysis to hydro‐electric turbine data and find that an exponential power distribution produces a well‐defined bathtub failure model when used with an imperfect repair assumption. We furthermore find that this bathtub model produces an improved fit over the equivalent Weibull model.
Electromigration in ALCu interconnections with W‐plug contacts
Authors: Ferlazzo L. , Reimbold G. , Gonchond J. P. , Heitzmann M. , Demolliens O. , Lormand G.
Published: July 2007

Tungsten is widely investigated for contact and via filling to improve planarization and step coverage. Although many electromigration data are available on multilayered structures, very few studies have been carried out on W‐plug structures and mainly concern the vias. This paper investigates the electromigration performance of W‐plug contacts and underlines the main failure modes. A comparison is made with classical contacts and W‐plug vias, pointing out a new failure mode.
Limitations of oxide breakdown accelerated testing for reliability simulation
Authors: Nafría M. , Suñé J. , Aymerich X.
Published: July 2007

Thin‐oxide MOS capacitors are analysed to reveal the limitations of oxide breakdown accelerated testing used for reliability simulations at the circuit level. The results show that the probability of failure can only be extrapolated from the tails of the statistical distributions.
Autoclave tests of 64 K and 256 K SRAMs
Authors: Polman H. L. A. , Fokkens K.
Published: July 2007

Results are presented of HAST tests of 64 K and 256 K SRAMs of 10 manufacturers at three temperature/humidity conditions. Failed memory cells are clustered in four different, manufacturer dependent, ways. A relation between the type of defect cluster and weaknesses in the manufacturing process is presented.
Tolerance design: Choosing optimal tolerance specifications in the design of machined parts
Authors: Jeang Angus
Published: July 2007

This paper provides a general approach for determining tolerances for machined parts which minimizes the combined machining cost and quality cost. We derive a mathematical model which takes into consideration both machining cost and quality cost, which depend on tolerance specifications and the distribution of the machined part dimension produced by a chosen machining process. The model represents the quality cost with a loss function and represents the machining cost with a fitted curve based on some original data. The distribution of the machined part characteristic is taken to be either normal or triangular, depending on model assumptions. By applying this model, designers can determine the tolerance which provides the minimum expected total cost.
A stochastic approach to consequence tree analysis
Authors: Schäbe Hendrik
Published: July 2007

In this paper a stochastic approach to consequence tree analysis is considered. A consequence tree is a set of events logically combined by OR and AND connections that occur in sequence, some being prerequisites for others. Consequence trees are applicable to failure propagation in plants. Facilitating paths and inhibiting cuts are defined and considered. The distribution of the time the system needs to reach a certain top event is obtained. Probability weights are defined that can be used to obtain the weakest link in the consequence tree.
Testing of the quality of solder joints through the analysis of their thermal behaviour with an interferometric laser probe
Authors: Claeys W. , Quintard V. , Dilhaire S. , Lewis D. , Danto Y.
Published: July 2007

We present an optical contactless method for testing the quality of solder joints in surface mounted components by measuring their thermal dynamic behaviour. We detect surface normal displacements induced by Joule heating with a high resolution interferometnc laser probe. This probing method, based upon a homodyne Michelson interferometer, is an interesting tool for investigating the mechanisms of heat deposition and flow inside electronic devices. It allows the precise time evolution of the surface normal displacement to be measured (the laser probe has subnanometric resolution).

This new approach of thermal behaviour laser testing is based upon the analysis of the diffusion of heat produced by the Joule effect in the structure (lead, solder and copper strip) from short current pulses and will influence heat diffusion. Solder joint failures (intermetallics, hidden voids, etc. ) behave as a thermal barrier. The optical test consists of measuring the dynamics of the solder joint expansion, and the variations from a standard response (good quality solder joints) will reveal defects. Important variations have been observed in solder joints that have undergone thermal cycling ageing tests.

We have also investigated the thermal response of joints on IMS (insulated metallic substrate) and epoxy substrates. They show a very different time response.