THE DEFENCE SPENDING–EXTERNAL DEBT NEXUS IN ETHIOPIA

The aim of this paper is to examine the impact of defence spending and income on the evolution of Ethiopia’s external debt over the period 1970–2005. Using the bounds test approach to cointegration and Granger causality tests, we find a long run and a causal relationship between external debt, defence spending and income. Defence spending had a positive and a significant impact on the stock of external debt while income had a negative and a statistically significant impact on external debt. Our findings suggest that an increase in defence spending contributes to the accumulation of Ethiopia’s external debt, while an increase in economic growth helps Ethiopia to reduce its external debt.     

TIME-VARYING CHARACTERISTICS OF SOUTH KOREA-UNITED STATES AND JAPAN-UNITED STATES MILITARY ALLIANCES UNDER CHINESE THREAT: A PUBLIC GOOD APPROACH

This paper investigates the nature of two military alliances under Chinese threat. The findings are as follows: First, South Korea does not consider China a significant threat while Japan and the United States have recognized China as a serious threat since the 1990s and the 2000s, respectively. Second, the relationship between South Korea and the United States is a true military alliance for all time periods, but the nature of the alliance has changed since the 1970s. Third, although Japan began to form an alliance relationship with the United States in the 1990s, Japan is considered a more significant ally by the United States. This paper implies that, should China provoke a military confrontation, it might be difficult to deduce a common solution among the three countries because of the different response to military threats from China.     

DOES MILITARY EXPENDITURE MATTER FOR INFLATION AND ECONOMIC GROWTH?

This paper sets up a monetary endogenous growth model, and uses it to explain the ambiguous linkage between the military burden and the inflation rate observed in existing empirical studies. It is found that an expansion in the military burden has an ambiguous effect on the inflation rate depending upon the relative extent of two conflicting forces. More specifically, if the increase in the marginal benefit from holding money exceeds (falls short of) the increase in the marginal product of private capital, the inflation rate will rise (fall) in response. Moreover, it is found that an increase in the military burden will stimulate the balanced growth rate, confirming Benoit’s famous empirical findings.     

一种用于GAF协议的优化邻居表算法

GAF协议是一种基于地理信息的无线传感器网络路由协议,由于采用多跳传输,将导致热区的产生。提出了一种优化邻居表算法,可以有效辨识GAF虚拟网格内的节点密度,从而选择密度大的网格通行,以均衡热区能耗,延长网络寿命。仿真结果验证了该算法的可行性。     

双频圆极化小型微带天线的设计与实现

文章设计了一种新型的单馈点双频圆极化小型微带天线,该天线采用层叠结构实现双频工作,利用两个半径不同的圆形贴片实现双频谐振;通过在上下贴片不同的对角线方向上开对称的圆孔实现圆极化和小型化。对该天线进行了仿真优化,结果表明天线工作在1.575 GHz GPS频段和2.08 GHz UMTS频段,工作频带上轴比性能良好,相比于没有开孔的圆形贴片天线尺寸减小13%左右,且具有较好的波瓣宽度。最后实际加工了相应的贴片天线并进行了测试,实测结果验证了这种设计的可行性。     

基于组合赋权雷达图实现电网电能质量综合评估

将改进的组合赋权雷达图方法用于电网电能质量综合评估。对主观、客观赋权法组合,基于组合权重与原权重之间的偏差尽可能小的优化思想,求取雷达图中各项指标的组合权值。利用各指标对应的扇形区域的对角线作为指标轴绘制雷达图,不仅最大限度体现各指标的独立权重,也反映了各指标之间的相互影响。利用雷达图的面积和周长两个变量完成对电能质量的综合评估。最后通过应用实例,验证了论文方法的合理性和在电能质量综合评估中的有效性。     

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