Demand forecasting by temporal aggregation

Demand forecasting performance is subject to the uncertainty underlying the time series an organization is dealing with. There are many approaches that may be used to reduce uncertainty and thus to improve forecasting performance. One intuitively appealing such approach is to aggregate demand in lower‐frequency “time buckets.” The approach under concern is termed to as temporal aggregation, and in this article, we investigate its impact on forecasting performance. We assume that the nonaggregated demand follows either a moving average process of order one or a first‐order autoregressive process and a single exponential smoothing (SES) procedure is used to forecast demand. These demand processes are often encountered in practice and SES is one of the standard estimators used in industry. Theoretical mean‐squared error expressions are derived for the aggregated and nonaggregated demand to contrast the relevant forecasting performances. The theoretical analysis is supported by an extensive numerical investigation and experimentation with an empirical dataset. The results indicate that performance improvements achieved through the aggregation approach are a function of the aggregation level, the smoothing constant, and the process parameters. Valuable insights are offered to practitioners and the article closes with an agenda for further research in this area. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 479–498, 2013     

Feeding Bread to the Luddites: The Radical Fundamentalist Islamic Revolution in Guerrilla Warfare

This study examines the war that the United States has waged since September 2001 as a global counterinsurgency. Placing the war against al-Qaeda and its allied groups and organizations in the context of a global insurgency also presents implications for doctrine, interagency coordination and military cultural change. The first part of the article offers a distilled analysis of al-Qaeda and its associated networks. The second section examines the US military in the context of the Western way of war, with the attendant military-cultural impediments to adapting to an enemy who embraces a very different approach to war. The third section aims to define and describe the nature of the war that America and its coalition partners are trying to wage. The concluding section offers the most value as it refines and distills the work of several international security and military thinkers to arrive at some imperatives for successfully prosecuting this type of war to its end.     

A Clash of Wills: Hizballah's Psychological Campaign Against Israel in South Lebanon

This article analyzes Hizballah's war against Israel in south Lebanon as a psychological contest where public opinion, perception, and persuasion were the real determinants of victory. Hizballah successfully mobilized popular support for its war by communicating nationalist and religious themes to different sectarian groups in Lebanon. At the same time, it used classic guerrilla warfare as a carefully calibrated psychological tool to erode the morale of Israeli forces, their Lebanese allies, and the Israeli public's support for the war. Hizballah's sophisticated media capability, particularly combat video footage aired on its satellite TV station and the Internet, played a critical role in amplifying the effects of its attrition campaign. By orchestrating information-age media and guerrilla tactics, this strategy has important implications for the future of irregular warfare.     

An American Trojan horse? Eisenhower,Latin America,and the development of us internal security policy 1954–1960

Perceptions of Third World nations as susceptible to communist subversion and revolutionary warfare led the Eisenhower administration to formulate a coordinated internal security strategy known simply as ‘1290d’. Later renamed the Overseas Internal Security Program (OISP), this policy initiative sought to strengthen host‐nation security forces, judicial systems, and public information media in an effort to combat indirect communist intervention strategies. Implementing OISP policy in Latin America proved difficult. In Congress, the administration was criticised for colluding with dictatorial regimes, while Latin Americans feared that the new program would be used as a ‘Trojan Horse’ to penetrate their security structures. After the Cuban Revolution, however, OISP policies developed under Eisenhower came to dominate US‐Latin American security relations for the remainder of the Cold War.     

The Demand for Military Spending in Egypt

Egypt plays a pivotal role in the security of the Middle East as the doorway to Europe and its military expenditure reflects its involvement in the machinations of such an unstable region, showing considerable variation over the last 40?years. These characteristics make it a particularly interesting case study of the determinants of military spending. This paper specifies and estimates an econometric model of the Egyptian demand for military spending, taking into account important strategic and political factors. Both economic and strategic factors are found to play a role in determining military burden/spending, with clear positive effects of lagged military burden, suggesting some sort of institutional inertia, plus negative output and net exports effects. The strategic effect as a result of the impact of Israel’s military burden is mostly positive and significant, though its impact is reduced when the impact of important strategic events are taken into account. The military spending of Egypt’s allies Jordan and Syria generally seems to have had no effect on Egypt’s spending. These results are consistent over a range of econometric techniques.     

UNFPA and population assistance

International population assistance in the UN is a relatively recent development; it is only since 1966 that a broad-based technical assistance program in population was authorized by the General Assembly. The desire of developing country members for accelerated economic growth ultimately brought about a change in the views on population. In 1967, the Secretary General established a trust fund for population activities, later renamed the United Nations Fund for Population Activities (UNFPA). 3 principles have guided UNFPA work since its inception: 1) national sovereignty in population matters is to be resspected and adhered to at all times, 2) individuals and couples are to be provided the information and services necessary to determine freely and responsibly the number and spacing of their children, and 3) population goals and policies are integral parts of socioeconomic defelopment. The areas of assistance by the UNFPA consist of 1) family planning, 2) communication and education, 3) population dynamics, 4) basic data collection, 5) population policy formulation and implementation, and 6) special programs such as those for women and the aging population. In 16 years, the UNFPA has received about $1.4 billion for transfer to developing countries as population assistanceand has financed 4373 population projects in 149 countries and territories. The relation between the US government and UNFPA is tenuous and likely to remain so as long as the US cannot resolve its own domestic controversies over famly planning, foreign population assistance, abortion, which, ironically, is legalin the country. There will always be some sort of domestic controversy over population; the UN has overcome domestic difficulties by framing the arguments properly within the demographic, social, economic, ecological, and political concerns of countries and applying the fundamental principles of national sovereignty, freedom of individual choice, and the link of population and development,to reconcile differences.     

Test for the extreme value and weibull distributions based on normalized spacings

Discussed in this article are tests for the extreme-value distribution, or, equivalently, for the two-parameter Weibull distribution when parameters are unknown and the sample may be censored. The three tests investigated are based on the median, the mean, and the Anderson-Darling A² statistic calculated from a set zⁱ of values derived from the spacings of the sample. The median and the mean have previously been discussed by Mann, Scheuer, and Fertig [10] and by Tiku and Singh [14]. Asymptotic distributions and points are given for the test statistics, based on recently developed theory, and power studies are conducted to compare them with each other and with two other statistics suitable for the test. Of the normalized spacings tests, A² is recommended overall; the mean also gives good power in many situations, but can be nonconsistent.     

Optimal replacement for fault-tolerant systems

We consider the optimal replacement problem for a fault tolerant system comprised of N components. The components are distingushable, and the state of the system is given by knowing exactly which components are operationl and which have failed. The individual component failure rates depend on the state of the entire system. We assume that the rate at which the system produces income decreases as the system deteriorates and the system replacement cost rises. Individual components cannot be replaced. We give a greedy-type algorithm that produces the replacement policy that maximizes the long-run net system income per unit time.