bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Release Rates for Cracks Caused by Moisture Absorption in Graphite/Epoxy Composites
Authors: Tsotsis T.K. , Weitsman Y.
Published: March 2007

Numerical and analytical calculations of the energy release rate or J- integral indicate that extremely low energies are involved in microcrack formation due to moisture absorption in graphite/epoxy materials. This suggests that moisture weakens the fiber-matrix interface by reducing the adhesion between graphite and epoxy. Additionally, since tensile stresses at the fiber-matrix interface were calculated to be substantially less than the matrix ultimate strength, it is concluded that moisture, and not any mechanical cause, creates damage around fibers when graphite/epoxy composites are exposed to humid environments.
Filament Winding Cylinders
Authors: Lee Soo-Yong , Springer George S.
Published: March 2007

By using the Lee-Springer filament winding model temperatures, degrees of cure, viscosities, stresses, strains, fiber tensions, fiber motions, and void diameters were calculated in graphite-epoxy composite cylinders during the winding and subsequent cur ing. The results demonstrate the type of information which can be generated by the model. It is shown, in reference to these results, how the model, and the corresponding WIND- THICK code, can be used to select the appropriate process variables.
Evaluation of Cylindrical Shear Joints for Composite Materials
Authors: Groves Scott , Sanchez Roberto , Lyon Richard , Magness Frank
Published: March 2007

The objective of this work was to evaluate the strength of four candidate cylindrical shear joints for composite tubes. The basic design for the joint entails an axial length of one inch with an external 15° tapered cone. The purpose of the joint is to transfer axial load from a cylinder through a steel shear attachment with a matching internal coni cal seat. The design candidates consisted of a bonded wedge cone, pinned wedge cone, and a bonded and pinned wedge cone attached to a two-inch diameter composite tube and a wedge cone integrally wound into the tube. The actual joint strengths achieved were higher than expected for some designs and were found to be dependent on the amount of hydrostatic or radial compression applied to the joint. The bonded wedge ring and the inte gral wedge ring both achieved over 96 MPa (14 ksi) of shear strength without failure. Due to the unexpectedly high shear strengths of the joints most of the failures were located in other parts of the test specimen. The bonded wedge cone was probably close to its maxi mum load carrying capacity while the integral wedge design showed potential for even higher shear strengths. The bonded and pinned joint reached a peak shear strength of 78.9 MPa (11.5 ksi) and the pinned only configuration achieved 70.6 MPa (10.3 ksi). When loaded without any hydrostatic compression the joint strengths were less than 34.3 MPa (5 ksi); however, the failure mode was hoop compression buckling of the tube itself as op posed to a joint shear failure.
Void Effects on the Interlaminar Shear Strength of Unidirectional Graphite-Fiber-Reinforced Composites
Authors: Bowles Kenneth J. , Frimpong Stephen
Published: March 2007

A study was conducted to evaluate the effect of voids on the interlaminar shear strength (ILSS) of a polyimide matrix composite system. The graphite/PMR-15 com posite was chosen for study because of the extensive amount of experience that has been amassed in the processing of this material. Composite densities and fiber contents of more than 30 different laminates were measured along with interlaminar shear strengths. Void contents were calculated and the void geometry and distribution were noted using micro scope techniques such as those used in metallography. A good empirical correlation be tween ILSS and composite density was found. However, the most acceptable relationship between the ILSS and density was found to be a power equation that closely resembles theoretically derived expressions. As the void content increased, an increase in scatter in the strength data was observed. In laminates with low void content, the voids appeared to be more segregated in one area of the laminate. We found that void-free composites could be processed in matched metal die molds at pressures greater than 1.4 MPa and less than 6.9 MPa.
Elastic Behavior of Woven Fabric Composites: II—Laminate Analysis
Authors: Shembekar P.S. , Naik N.K.
Published: March 2007

Two-dimensional models are presented for the elastic analysis of the plain weave fabric laminates. A methodology to generate the laminate configuration from the lamina configuration is given. The effect of lamina configuration and their relative posi tions with respect to each other on the in-plane elastic constants of the woven fabric lami nates is studied. A laminate configuration with optimum shifts gives higher elastic proper ties compared to the other configurations. A comparison between in-plane elastic moduli of the unidirectionally laminated symmetric cross-ply laminates and plain weave fabric laminates is made. The in-plane elastic moduli of plain weave fabric laminates predicted by the models are found to be in good agreement with the experimental results.
Numerical Verification of a Procedure for Calculation of Elastic Constants in Microcracking Composite Laminates
Authors: Gudmundson Peter , Östlund Sören
Published: March 2007

In two recent papers Gudmundson and Östlund have presented a simple to use theory for calculation of reduced thermoelastic constants in composite laminates with matrix cracks. The theory is valid for two- and three-dimensional laminates of arbitrary layups and is asymptotically exact for dilute and infinite microcrark densities. Further more, the theory is based solely on ply property data and matrix crack densities. No ex perimentally determined or unknown theoretical parameters are required. The theory pre dicts changes in all coefficients of the elastic stiffness and thermal expansion coefficient tensors.

In previous papers the accuracy of the present theory has been investigated for cross ply laminates by comparisons to experimental results from the literature and two-dimensional finite element calculations. However, in order to become a powerful tool in the analysis of cracked composite laminates the theory must be verified at intermediate crack densities also for angle ply laminates. Unfortunately no useful experimental results for such lami nates have been found in the literature and numerical methods must be considered for the verification. In the present paper the approximate theory is compared with three- dimensional finite element calculations of cracked thick [⊖, - ⊖ ] M glass fiber reinforced epoxy laminates for a wide range of different matrix crack densities. The finite element calculations can be considered as exact for all crack densities within the present formula tion, and errors are due only to the numerical algorithm. It is found that the dilute theory in combination with the theory for infinite crack densities to a surprisingly good accuracy cover all ranges of crack densities.
The Effect of Seawater Exposure on Mode I Interlaminar Fracture and Crack Growth in Graphite/Epoxy
Authors: Sloan Forrest E. , Seymour Richard J.
Published: March 2007

The effects of seawater exposure on the mechanics of Mode I fracture and crack growth in unidirectional AS-4/3501 graphite/epoxy were investigated utilizing the previously developed compliant load-frame (CLF) technique. Mode I double-cantilever- beam (DCB) specimens were exposed to fresh flowing seawater under both static and fa tigue loading conditions. Long-term fatigue loading in air resulted in extensive bridging of reinforcing fibers across the crack tip, increasing the apparent fracture resistance of the material. The primary effect of seawater was to weaken the fiber-to-matrix bond in the composite, causing an increase in the number of bridged fibers. Fiber bridging increased the fracture resistance of the DCB test specimens and reduced the rate of crack growth to near zero. An increase in the fracture resistance of specimens soaked in seawater but not loaded was also attributed to a weakened fiber-to-matrix bond. The compliant load-frame (CLF) technique was found to be a simple and cost-effective method for studying the mechanics of crack growth under environmental exposure conditions. However, linear- elastic fracture mechanics (LEFM) relationships derived previously for the CLF become invalid when the fracture resistance of the material increases during crack growth, e.g., during fiber bridging.
Vibrations of a Composite Cylindrical Shell Made of a Glass Reinforced Plastic Material
Authors: Roscoe A.J. , Lu Y.P.
Published: March 2007

The vibrational characteristics of a composite cylindrical shell were ex perimentally determined and evaluated. The composite cylindrical shell, which is com mercially available, is made of a glass reinforced plastic material. An impedance test was conducted to study the effectiveness of damping and vibration related properties of the composite. For comparison purposes, an identical test was conducted on a cylindrical shell made of steel. Impedance results are presented, discussed and compared between the com posite shell and the steel shell. The significance of this article is that the forced vibrational characteristics of a glass reinforced plastic composite shell are evaluated in an impedance format, and are compared with those of an equivalent shell made of steel.
Finite Element Modelling of the Stress Distribution in Polymer Composites with Coated Fibre Interlayers
Authors: Nassehi V. , Kinsella M. , Mascia L.
Published: March 2007

In this paper we present a mathematical model for the analysis of the in fluence of interlayers on the stress distribution around cylindrical fibres resulting from deformations of the fibre/polymer composites in the transverse directions. The model is based on the Galerkin finite element technique in conjunction with a penalty method, which is normally used to model the flow of incompressible non-Newtonian fluids. The advantage of this method is in its ability to cope very effectively with the non-linear defor mations. Such deformations are frequently found in polymeric composites. We have adapted this approach to solid systems and used it to model deformations of composites containing coated fibres. The modulus and thickness of coating layers was changed to cover a range of behaviour, varying from that of a typical rubbery material to ductile ther moplastics. In order to show the validity of our approach we have compared the computed results with known solutions from other published works and some experimental data.
Modelling of 90° Ply Cracking in Crossply Laminates, Including Three-Dimensional Effects
Authors: Guild F.J. , Ogin S.L. , Smith P.A.
Published: March 2007

The mechanics of transverse ply cracking in crossply composite laminates is examined in detail. A three-dimensional finite element model has been developed. This has been used to calculate fracture mechanics parameters associated with transverse ply crack growth across the width of a glass fibre reinforced epoxy (GFRP) laminate. The pre dictions of the model are shown to be in good agreement with existing shear-lag analyses and experimental results from the literature. The finite element analysis provides addi tional insight into the mechanics of the problem; in particular it is shown that variations of fracture mechanics parameters as a transverse crack grows across the width of a lami nate are minor.
On the Mechanics of Thin-Walled Laminated Composite Beams
Authors: Barbero Ever J. , Lopez-Anido Roberto , Davalos Julio F.
Published: March 2007

A formal engineering approach of the mechanics of thin-walled laminated beams based on kinematic assumptions consistent with Timoshenko beam theory is pre sented. Thin-walled composite beams with open or closed cross section subjected to bend ing and axial load are considered. A variational formulation is employed to obtain a com prehensive description of the structural response. Beam stiffness coefficients, which account for the cross section geometry and for the material anisotropy, are obtained. An explicit expression for the static shear correction factor of thin-walled composite beams is derived from energy equivalence. A numerical example involving a laminated I-beam is used to demonstrate the capability of the model for predicting displacements and ply stresses.
Siblings, Birth Order, and Cooperative-Competitive Social Behavior
Authors: Knight George P. , Kagan Spencer
Published: March 2007

Several researchers have suggested that the consistently found Anglo-American/ Mexican-American difference in cooperative-competitive social behavior is at least partly a result of the relatively larger Mexican-American family size. To test that hypothesis, 126 Anglo-American and 63 Mexican-American children were administered the Social Behavior Scale and their mothers were interviewed to determine the number of siblings and the ordinal position of the child. The results revealed cultural, age, and sex differences similar to those obtained in previous studies, and indicated that the Mexican-American children did indeed have more siblings and differed significantly in birth order compared to the Anglo-American children. However, the results did not demonstrate a significant relation between cooperative-competitive social behavior and the number of siblings or birth order; and after statistically controlling for the number of siblings and birth order, the cultural, age, and sex difference in cooperative-competitive social behavior remained statistically significant. The results are discussed in terms of alternative explanations of the observed cultural difference.
Accurate Perception of Colored Illustration
Authors: Modiano Nancy , Maldonado P. Luz Maria , B. Susana Villasana
Published: March 2007

While there have been many studies of the comprehension of different styles of black and white visual stimuli by nonliterate populations, little has been done with colored illustrations. Since the latter are becoming more accessible worldwide, it was found necessary to determine what types would be easiest for children from these groups to perceive. Paintings and photographs of familiar subjects, taken from readily available textbooks, were shown to 71 6-year-olds from six Mexican-Indian groups to determine their overall rate of comprehension (80%) and the effect of the medium on perception. There were no significant differences in comprehension between media (photographs and paintings), but there were between the sexes and between two of the ethnic groups.
Is Transnational Terrorism Becoming More Threatening?
Authors: Enders Walter , Sandler Todd
Published: March 2007

This study applies time-series techniques to investigate the current threat posed by transnational terrorist incidents. Although the number of incidents has dropped dramatically during the post-cold war period, transnational terrorism still presents a significant threat. In recent years, each incident is almost 17 percentage points more likely to result in death or injuries. Three alternative casualties series (incidents with injuries and/or deaths, the proportion of incidents with casualties, and incidents with deaths) are investigated. These series increased in November 1979 with the takeover of the U.S. embassy in Tehran and again after the fourth quarter of 1991. The growth of religious terrorism appears to account for the increased severity of terrorist attacks since the last quarter of 1991. All three casualties series displayed more deterministic factors than the noncasualties series, which is largely random after detrending. Cycles in the aggregate incident series are solely attributable to the underlying casualties series.
Modeling the Democratic Peace as a Kantian Selection Process
Authors: Cederman Lars-Erik
Published: March 2007

Computational modeling is used to improve our understanding of how the democratic peace unfolds as a historical process in time and space. Whereas most of the conventional literature interprets the phenomenon as a constant and universal law operating at the state level, the author follows Immanuel Kant and treats democratic cooperation as an emergent macroprocess. The current study explores three causal mechanisms. First, strategic tagging introduces a way for democracies to select out like-minded cooperators. Second, regime-sensitive alliances enable democratic states to defend the gains of cooperation. Third, liberal collective security complements the liberal alignments. Based on these processes, it is possible to “grow” cooperative outcomes in an inhospitable geopolitical environment. Because tagging alone is insufficient, alliances, and sometimes even collective security, are necessary to produce perpetual peace. Such outcomes are characterized by high levels of spatial clustering.
Turning Points in International Negotiation
Authors: Druckman Daniel
Published: March 2007

A turning-points analysis of 34 cases of international negotiation is performed in three parts: precipitants (external, substantive, or procedural), process departures (abrupt or nonabrupt), and immediate and later consequences (escalatory or de-escalatory). The cases are divided into three types according to issue area: security, political (including environmental), and trade or economic negotiations. The results are summarized in terms of paths to outcomes: security negotiations are characterized primarily by external precipitants leading to abrupt departures in process that typically turn the talks in the direction of agreements; process departures or turning points in political and trade talks are usually precipitated by either substantive or procedural decisions made by the negotiators that also lead to agreements. Implications of the findings are discussed in terms of the risk-averse and reactive orientations taken by governments in the area of security policy. They are also discussed in the context of strengths and limitations of the comparative analysis approach and in relation to analyses of 11 cases of domestic negotiations in the airlines industry.
Exploring the Dynamics of the Democratic Peace
Authors: Cederman Lars-Erik , Rao Mohan Penubarti
Published: March 2007

In quantitative models of international conflict, the variables' causal effects are generally assumed to be constant over historical time. Yet, qualitative liberal theorizing, especially that of Immanuel Kant, has tended to emphasize a dynamic perspective based on the theme of progress. To bridge this gap between method-imposed stasis and theoretical dynamics, a framework featuring time-varying parameters is applied to the democratic peace hypothesis. The model strongly confirms a dynamic reinterpretation of Kant's theory. Results show that dispute probabilities decline steadily among democratic states over time, and the democratic peace hypothesis is not just a transient cold war effect. This result is robust to statistical control involving geopolitical and liberal control variables, including alliances, capabilities, and economic development.
Economic Determinants of Political Unrest
Authors: Parvin Manoucher
Published: March 2007

Some degree of political unrest and thus potential for violence exists in all societies at all times. In recent years, the causes of political unrest are attributed to one or more sociopsychological traits or geopolitical factors. Economic explanations are absent or lack modern quantitative approach. This study is an attempt to test some of the old and new theories of political unrest, and to extend, modify, and synthetize others in a unified theoretical framework. Thus, etiologically, universal economic factors in contrast to noneconomic, particular, or local factors are considered and methodologically a multifactor analysis is adopted. Theoretically, neither exclusivity nor primacy of economic factors is assumed; however, empirical results demonstrate their importance as main explanatory variables of political violence. In contrast to general belief, it is shown that political unrest is not a monotonically explained variable for the entire range of explanatory factors such as relative deprivation. Thus, the usefulness of concepts such as optimum level of income inequality, socioeconomic mobility, income growth rate, or the like are indicated.
The Policy Basis of General Purpose Forces
Authors: Dennis Michael F.H.
Published: March 2007

A model based on Allison (1969, 1971) and Richardson (1970) links underlying policies to general purpose force procurement. "Popular" desires lead to overall procurement levels which are stable over a long period. A lasting bureaucratic equilibrium determines service procurement shares. Overall procurement is unaffect ed by transnational inputs. Intraservice perceptions, not national strategic posture changes, cause changes in systems types procured. The determination of naval policies from procurements 1950-1970 of France, United Kingdom, United States, and USSR validates the model.
Power, Uncertainty, and the Onset of International Violence
Authors: Midlarsky Manus I.
Published: March 2007

This study suggests a particular conceptualization of power for purposes of explaining the onset of international warfare. Power is here understood as a capability to effect a reduction of environmental uncertainty, while the exercise of power for the benefit of an actor is the actual reduction of that uncertainty. Eight types of power configuration are specified, including, among others, control, subservience, constraint, and inversion. The conditions of power loss in alliance systems and power constraint in the form of geographical frontiers are found to be related to the frequency of war for central power nations. An alternative approach stemming from theories of international stability yields the same functional relationship as does the initial power framework. Additionally, a logarithmic relationship is found between the number of international poles existing in the period 1815-1945 and the frequency of war. Policy implications are derived relative to alliance-formation and responses to the emergence of new polar actors.
The Finite Negotiation Problem
Authors: Rice Peter
Published: March 2007

A finite negotiation problem is a finite, two-person, non-zero-sum noncooperative game. A negotiated solution to a problem is an outcome associated with two pure strategies, one for each player, which is arrived at by a negotiation process. The problem posed and solved in this article is the specification of a solution theory which reflects the expectations of negotiators and captures the strategic possibilities implicit in the original game. Instead of approaching the theory through axioms which imply the existence of a unique solution, this study describes a negotiating scenario which, when exactly described, is itself a game. Given the information of who moves first in the negotiation game, there is an equilibrium outcome, and this is taken as the solution of the problem.
An Analysis of Final-Offer Arbitration
Authors: Farber Henry S.
Published: March 2007

A model of the final-offer arbitration (FOA) process is developed, and the Nash equilibrium pair of final offers is derived. It is shown that the more risk-averse party submits a more reasonable offer so that it has a higher probability of being chosen by the arbitrator. The contract zone of potential negotiated settlements is derived, and its size is shown to be directly related to the uncertainty of the parties concerning the arbitrators' preferences. However, the final offers of the parties diverge where there is increased uncertainty, so that there is a trade-off between the size of the contract zone and the extremity of arbitrated awards when negotiations do fail. Finally, it is shown that negotiated settlements under FOA are skewed against the more risk-averse party.
Reward, Punishment, and Interdependence
Authors: Rosecrance Richard
Published: March 2007

This essay seeks to show that the successful use of reward and punishment is related to the degree of interdependence among the parties. Where the relationship is one of "independence," A cannot influence B using either technique. Where the relationship is one of "interdependence," rewards and punishments can be easily given, and they are likely to be of influence. On the other hand, once given it will not be easy to withdraw "rewards." Thus no unilateral influence process is established. Where the relationship is one of "dependence" of B on A, both "rewards" and "punishments" are influential. The analytical conclusions of the essay are used to help explain why World War II could not have been prevented using "rewards" and why World War I (under different circumstances of sensitivity to opponent interests) might have been obviated or postponed by the judicious use of "reward."
Horse Races, Security Markets, and Foreign Relations
Authors: Chan Steve , Bobrow Davis B.
Published: March 2007

We report an attempt to use financial market data to predict the onset of a variety of international crises. A quasi-experimental design for studying interrupted time series data is applied to the historical behavior of the Hong Kong and New York financial markets. The results are generally disappointing. These markets seem more likely to react to rather than anticipate crisis developments, and frequently issue "false alarms." Comparison of results for periods where crises took place with those for randomly selected periods where no crisis happened does not engender confidence in markets as crisis predictors. However, there are some notable exceptions to this pessimistic generalization. We conclude that financial indicators may be profitably used in some cases to supplement warning assessments derived from other methods and sources.
Confounding the Creation of Social Forces
Authors: Duffy John F. , Kavanagh Michael J.
Published: March 2007

Many studies of bargaining behavior use an experimental paradigm in which a role play manipulation is contrasted with a “real” social force manipulation. These design changes confound the results because the experiment's social forces are created by two qualitatively different methods (role play versus “reality”) which are not quantitatively controlled. The present study replicates a previous experiment with this paradigm as a control condition and remedies the design problems as an experimental condition. The confounding is evident since a significant difference between control and experimental conditions is found. These results suggest that (1) methodologically, previous studies using the confounded design are tenuous; (2) contextually, loyalty does not have a significantly stronger influence on a negotiator than the need for logic; and (3) the group processes that affect the outcome are not obvious, although three post hoc explanations are proposed for future investigation.
Modeling the Role of Conflict and Conciliation in Bargaining
Authors: Saraydar Edward
Published: March 2007

So as to provide a more general framework for an analysis of those factors that can influence the outcome of bargaining under a situation of uncertainty, this article develops an adaptive-expectations multisized-concession paradigm of bargaining. The firmness with which bargainers hold to their positions is a function of the expected utility of the potential payoffs associated with alternative moves, and the size of alternative concession prospects is considered implicitly in relationship to the differential effect on subjective probability distributions. The construct permits the development of the role of bargaining as a communicative device, designed to transmit and receive information, create and dispel uncertainty. Bluff and notbluff are discussed as tactics of conflict and conciliation, within the context of a relationship between the manifest bargaining stance of bargainers and their actual commitment to their current demand. The “loss of face” factor involved in concession moves is explored, as well as the role of time and timing as bargaining tactics. Finally, quid pro quo is discussed as a tactic of conciliation, together with the constituents of what might be termed an optimum bargaining behavior.
Proliferation, Deterrence, and the Likelihood of Nuclear War
Authors: Berkowitz Bruce D.
Published: March 2007

Two arguments have traditionally been made about the effects of proliferation on the likelihood of nuclear war. One argument claims that proliferation increases the likelihood of nuclear war; the other claims that proliferation reduces the likelihood of nuclear war. This article shows that, in fact, both of these arguments are logical and probably true some of the time. The key factor that decides when one argument is more valid than the other is the degree to which nuclear powers can deter other nuclear powers. Because the conditions necessary for stable deterrence can vary systematically, it is possible to define when proliferation is a threat and when it is an asset. Moreover, using these principles, the article analyzes the effect of previous cases of proliferation on the likelihood of war, and shows how a compromise policy for dealing with proliferation can best be determined.
Internal and External Conflict and Violence
Authors: Ross Marc Howard
Published: March 2007

A general theory of conflict and violence (Ross, forthcoming) can help in understanding the relationship between internal and external conflict. Looking at a sample of 90 preindustrial societies supports the proposition that the two have a moderate, positive relationship. More important, however, the analysis identifies conditions under which the two forms of political conflict are associated, and those under which they are differentiated. The strength and patterns of cross-cutting ties are very different in societies in which internal and external conflict covary and societies in which internal and external conflict are independent. Similarly, the structural features of society are central determinants of whether targets of overt aggression are within a society, located outside it, or both. Finally, dispositional (psychocultural) characteristics found in a society are the best predictors of overall conflict levels, but are not useful in distinguishing between internal and external targets. In the conclusion the elements of a general theory of conflict involving both structural and dispositional considerations are elaborated.
Arms Control Verification
Authors: Pieragostini Karl
Published: March 2007

The arms control experience of the past 25 years has shown verification to be the key to the future success of formal arms control agreements, and has highlighted how crucial cooperation is to the verification effort. Unfortunately, fundamental disagreement persists within the United States over what we should expect from verification, and we seem to have lost sight of how far we have come with the Soviet Union. The first half of this article outlines the questions involved in the debate over verification, how much of it is enough, and what we should do about suspected cheating. This lays the groundwork for a detailed discussion of the precedents already established for cooperative verification. These include measures to foster resolution of treaty-related problems, increase the effectiveness of national technical means, provide for on-site inspection, and allow the use of “black box” sensors. These precedents represent considerable progress of which we should remind ourselves, especially at a time when they may be placed in jeopardy by our more recent lack of success in arms control.
Trust and the Consumption of a Deteriorating Common Resource
Authors: Brann Peter , Foddy Margaret
Published: March 2007

This study examines the relationship between generalized expectations about others' behavior (interpersonal trust) and consumption of a regenerating resource in a simulated commons dilemma. Eighty subjects were assigned to one of four feedback conditions in a split-plot factorial design (trust X feedback X blocks). Resources were programmed to deteriorate at four different rates. However, subjects believed they were acting in groups of five, and that resource deterioration was a consequence of the rate of consumption of the resource.

When faced with minimal deterioration of the resource pool, subjects increased their consumption over trial blocks; rapid deterioration led to decreased consumption. However, the consumption rate of low trusters was unaffected by the rate at which the resource deteriorated. High trusters consumed more than low trusters when resource deterioration was minimal, but significantly less than low trusters under conditions of rapid deterioration. The results give support to the claim that trust plays an important role in mediating resource consumption in commons dilemmas.
Foreign Policy and the Rational Public
Authors: Shapiro Robert Y. , Page Benjamin I.
Published: March 2007

American public opinion about foreign policy is neither volatile nor capricious. Contrary to much conventional wisdom, collective opinion has tended to be rather stable. When it has changed, it has done so by responding in rational ways to international and domestic events that have been reported and interpreted by the mass media and by policymakers and other elites. The public has not always successfully judged the best interests of the United States or that of people elsewhere, nor have elites and the media always reported truthfully and interpreted correctly. Nevertheless, we maintain that Americans, as a collective body, have done well with whatever information has been provided, and that they have formed and changed their policy preferences in a reasonable manner. This conclusion is based upon analysis, both quantitative and historical, of a comprehensive set of data on foreign policy opinion changes in the United States from the 1930s to the 1980s.
Trading Public Goods in the Western Alliance System
Authors: Boyer Mark A.
Published: March 2007

This article seeks to broaden the scope of analyses of security burden sharing within the Western alliance system beyond the narrow military approach taken by past work in the economic theory of alliances. In contrast to that work, which has shown that the Western allies have been persistently free riding on the military efforts of the United States, an illustrative model is presented that posits the existence of burden sharing across issue areas among the Western allies. The model yields significantly different conclusions regarding (1) the nature of alliance burden sharing, (2) the optimality of alliance security provision, and (3) the future of cooperation in the Western alliance system in the face of declining American hegemony. On a theoretical level, this article begins to formulate a new economic theory of alliances that focuses on “trade” in public goods and adheres closely to the Ricardian theory of comparative advantage. I hypothesize that nations will specialize in the production of those alliance goods (economic, political, and military) for which they possess comparative advantages. This hypothesis is given preliminary support through an examination of allied expenditures on the military and foreign aid.
Port Access and Arms Sales
Authors: Hunt W. Ben
Published: March 2007

This article examines the strategic use of arms sales by the Soviet Union. It is concerned with how the USSR, through its arms sales, rewards clients who give it what it wants and punishes clients who do not. This study identified grants of port access and, to a lesser degree, ability to pay in hard cash as the virtually exclusive determinants of variation in the contract terms of Soviet arms sales.
The Concentration of Capabilities and the Onset of War
Authors: Mansfield Edward D.
Published: March 2007

Recent empirical research has produced no consensus on what (if any) relationship exists between the concentration of capabilities and the onset of war. The results of this article indicate that concentration is related to the frequency of war, but that rather than the monotonic relationship predicted by both balance of power and power preponderance theories, the relationship appears to have an inverted U-shape. We also show that concentration can be disaggregated into: (1) the number of major powers, and (2) the inequality of capabilities among the major powers. Our analysis shows that both components influence war, but that the effect on war of each component of concentration depends on the level of the other.
Reciprocity and Norms in U.S.-Soviet Foreign Policy
Authors: Ward Michael D. , Rajmaira Sheen
Published: March 2007

This study examines the nature of U.S.-Soviet relations over the past 4 decades. The authors focus especially on the 1980s. There has been a marked shift in U.S.-Soviet conflictual and cooperative foreign policy behavior subsequent to Gorbachev's rise to power. The authors explore quantitatively the changes in conflictual and cooperative behavior in the context of reciprocity and evolving norms. Using event data from 1948 through 1988, they analyze the role of reciprocity in U.S.-Soviet relations as well as the nature of underlying norms that set broad parameters for U.S.-Soviet foreign policy behavior. Time-varying parameter estimates of memory and reactivity for both countries, as well as the interaction propensities of successive heads of state, suggest an increase in cooperation and a leveling off of hostility between the United States and the Soviet Union since 1985.
The Role of Communication in Interindividual-Intergroup Discontinuity
Authors: Insko Chester A. , Schopler John , Drigotas Stephen M. , Graetz Kenneth A. , Kennedy James , Cox Chante , Bornstein Garry
Published: March 2007

The present research was designed to explore the role of communication on interindividual-intergroup discontinuity in the context of the PDG-Alt matrix. (The PDG-Alt matrix is a prisoner's dilemma game matrix that adds a third withdrawal choice to the usual cooperative and uncooperative choices of the PDG matrix, and interindividual-intergroup discontinuity is the tendency of intergroup relations to be more competitive and less cooperative than interindividual relations.) Several predictions implied by the fear and greed explanations of interindividual-intergroup discontinuity were tested. One prediction, an implication of the fear hypothesis, is that communication should produce a larger increase in the cooperation of individuals than of groups. This prediction is based partially on the assumption that the outgroup schema, which leads to more fear of groups than of individuals, should reduce the credibility of between group communication. Given, however, that without communication individuals may not cooperate, what will they do? Will they withdraw or will they compete? Another prediction, an implication of the greed hypothesis, is that the absence of communication should result in a greater increase in withdrawal for individuals than for groups. This prediction is based partially on the assumption that the social support provided to fellow group members for self-interested competitiveness is absent for individuals. These predictions were confirmed. It was argued that the lesser tendency of individuals to cooperate when there is no communication with the opponent may explain partially the differing results of past discontinuity research (which has involved communication) and research reported in the PDG literature (which typically has not involved communication).
The Situational Levers of Negotiating Flexibility
Authors: Druckman Daniel
Published: March 2007

The effects of a number of situational variables on decisions to be flexible or inflexible were explored in a simulation of an international negotiation on the regulation of gases contributing to the depletion of the ozone layer. Four negotiating-stage scenarios were created, each consisting of a particular combination of variables arranged into three experimental conditions. The experiment was run with two international samples, one consisting of scientists, the other of diplomats from different countries. The hypothesized differences among the conditions were obtained for both samples. Using a pair-comparisons format, participants were asked to judge the relative importance of the variables, within stages, in producing flexibility. Analyses of these judgments revealed trajectories of factors leading to agreement or to stalemate for both samples. These results were also compared with those obtained from a meta-analysis of earlier experiments examining similar variables. The simulation results, based on combined impacts of variables, were stronger than those obtained in the earlier experiments where variables were manipulated one at a time.
Community and Industrial Mediation in South Korea
Authors: Kim Nam Hyeon , Wall James A. , Sohn Dong-Won , Kim Jay S.
Published: March 2007

This study investigates the mediations of 95 community and 95 industrial mediators in South Korea. The mediators' reports of their last mediation indicated the frequency with which they used 36 mediation techniques. In addition, their information revealed the strategies—data gathering, reconciliation, dependency, analysis—they employed in their mediations. We expected to find the data gathering and reconciliation strategies. Although unexpected, the dependency strategy is very consistent with the Confucian emphasis on interpersonal harmony. And we attribute the analysis strategy to the Korean mediators' low formal power or to their exposure to an industrialized environment.
Linkage Politics
Authors: Lohmann Susanne
Published: March 2007

In this article, the author extends the basic repeated prisoners' dilemma to allow for the linkage of punishment strategies across issues (issue linkage) as well as decentralized third-party enforcement (player linkage). The concepts of issue and player linkage are then synthesized to develop the notion of domestic-international linkage, which connects trigger strategy punishments across games played over different issues by different sets of players. In a two-level game, domestic and international cooperation may be reinforced by a punishment linkage; a defection in the domestic game may trigger a breakdown of international cooperation and vice versa. The author also examines the conditions under which the incentives to cooperate are stronger at the domestic level than at the international level and vice versa. With domestic-international linkage, the credibility surplus on one level spills over to offset the credibility deficit on the other level. Finally, the author provides conditions under which governments are better off delinking domestic and international issues.
The Dissemination of Culture
Authors: Axelrod Robert
Published: March 2007

Despite tendencies toward convergence, differences between individuals and groups continue to exist in beliefs, attitudes, and behavior. An agent-based adaptive model reveals the effects of a mechanism of convergent social influence. The actors are placed at fixed sites. The basic premise is that the more similar an actor is to a neighbor, the more likely that that actor will adopt one of the neighbor's traits. Unlike previous models of social influence or cultural change that treat features one at a time, the proposed model takes into account the interaction between different features. The model illustrates how local convergence can generate global polarization. Simulations show that the number of stable homogeneous regions decreases with the number of features, increases with the number of alternative traits per feature, decreases with the range of interaction, and (most surprisingly) decreases when the geographic territory grows beyond a certain size.
Democracy and Compromise in Militarized Interstate Conflicts, 1816-1992
Authors: Mousseau Michael
Published: March 2007

Research has documented that democratic nations are about 30 times less likely to originate interstate wars and about 3 times less likely to originate militarized interstate disputes among themselves than other types of regimes. Compromise is a means for resolving conflict whereby disputants agree to mutual concessions. Many researchers contend that compromise is among the central defining features of democratic political culture. If a norm of compromise can explain the absence of wars between democratic nations, then one should expect to find a democratic inclination toward compromise in the path from the initial militarization of an interstate conflict to all-out war. An analysis of militarized interstate disputes originating as one-on-one confrontations occurring worldwide from 1816 to 1992 reveals robust support for the proposition. The results indicate that joint highly democratic dyads are about 3 times more likely than joint highly autocratic dyads to resolve their militarized conflicts with mutual concessions.
Probabilistic Coalition Structure Theories
Authors: Michener H. Andrew , Myers Daniel J.
Published: March 2007

This article reports a comparative test of the central-union theory in four-person sidepayment games. Predictions by two variants of central-union theory (CU-1 and CU-2) are tested vis-à-vis predictions by three other solutions (the equal excess model, the Myerson-Shapley solution, and the kernel). With respect to players' payoffs, results show that CU-1, CU-2, equal excess, and Myerson-Shapley models have essentially equal predictive accuracy and that all of these are superior to the kernel in the test games. However, when coalition structure probability predictions are incorporated in the test, both CU-1 and CU-2 emerge as more accurate than all the other models tested.
On the Nature of First Democratic Elections
Authors: Wantchekon Leonard
Published: March 2007

This article investigates voting behavior and policy outcomes when violence can occur after the election. The author finds that under complete information, voters will prefer the weak party—that is, the party that is the least capable of controlling violence. Under incomplete information, however, violence might occur, and voters could prefer the party the most capable of controlling violence. Finally, the author shows that despite this likely voting outcome, the weak party will choose to participate nonaggressively in the election, providing legitimacy to the new democratic process.
Regime Type, Strategic Interaction, and the Diversionary Use of Force
Authors: Miller Ross A.
Published: March 2007

This study explores the relative propensity of democratic and autocratic regimes to engage in diversionary behavior. Although previous research has focused on the willingness of leaders to engage in conflict, recent studies suggest an alternative explanation: the effect of strategic interaction opportunities. Previous studies suggest that even though democratic leaders may have an incentive to use foreign policy to manipulate domestic audiences, would-be adversaries limit their interaction opportunities. This article extends the analysis to a comparison of the behavior of democratic and autocratic regimes. Using three different indicators of the domestic political vulnerability of leaders—economic growth rates, protests, and rebellions—the results indicate that democratic leaders are apparently more affected by strategic interaction opportunities than their autocratic counterparts.
Nonunitary Actors in Spatial Models
Authors: Hug Simon
Published: March 2007

Spatial models are increasingly finding entrance into the analysis of international relations. These models are perfectly appropriate as long as the relevant policy or negotiation space is unidimensional or the actors are truly unitary. But the recent discovery of the domestic arena questions the appropriateness of the unitary actor assumption. Hence, using spatial models becomes questionable. This article discusses the limitations of spatial models in this context and shows under what conditions the nonunitariness of actors poses no problems.