Dimensional Reduction, Seiberg--Witten Map and Supersymmetry

It is argued that dimensional reduction of Seiberg-Witten map for a gauge field induces Seiberg-Witten maps for the other noncommutative fields of a gauge invariant theory. We demonstrate this observation by dimensionally reducing the noncommutative N=1 SYM theory in 6 dimensions to obtain noncommutative N=2 SYM in 4 dimensions. We explicitly derive Seiberg-Witten maps of the component fields in 6 and 4 dimensions. Moreover, we give a general method to define the deformed supersymmetry transformations that leaves the actions invariant after performing the Seiberg-Witten maps.Comment: 14 pages. One Ref. added. To appear in PR

Relaxation Of Brownian Particles In A Gravitational Field

We describe an upper level undergraduate experiment on the time-dependent behavior of a suspension of Brownian particles under gravitational attraction. We employed the Fokker-Planck equation in the strong friction limit and measured the time-evolution of the probability distribution for 1.0 mu m diameter latex Brownian particles in water at room temperature and pressure. The experiment provides evidence of the atomic nature of water.Physic

Çelik Çerçevelerin LRFD-AISC Şartnamesine Göre Av Arama Optimizasyon Yöntemi Kullanılarak Optimum Boyutlandırılması

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bu çalışmada çelik çerçeveler için av arama optimizasyon yöntemini temel alan bir optimum tasarım algoritması sunulmaktadır. Aslan, kurt ve yunus gibi hayvanların gurup olarak avlanmalarından esinlenilerek geliştirilmiş olan av arama optimizasyon yöntemi de bu tekniklerin son dönemlerde ön plana çıkanlarından biridir. Bu avcılarıjn her biri avlanmalarını farklı şekillerde gerçekleştirir. Fakat ortak yönleri grup içinde birlikte av aramalarıdır. Avın etrafı çembere alınır ve yakalanana kadar çember daraltılır. Mevcut çalışmada av arama tekniği çerçeve optimizasyon algoritmasının otomasyonu için kullanılmıştır. İki boyutlu çelik çerçevelerin optimum tasarımının gereği olarak; yapı elemanlarının W profiline uygun olması, LRFD-AISC tasarım şartnamelerindeki sınırlayıcıları sağlaması ve çerçevenin minimum ağırlığa sahip olması gerekmektedir. Bu amaçla burkulmayı da hesaba katan dayanım sınırlayıcıları göz önünde bulundurulmuş ve algoritmanın kolon ve kirişler için Amerikan Şartnamesindeki 272 kesit içerisinden seçim yapması sağlanmıştır. Her bir grup içindeki elemanlara aynı kesitin tayin edilebilmesi için eleman gruplandırılması yapılmıştır. Şartnamedeki sınırlayıcıları dikkate alarak minimum çerçeve ağırlığını hesaplayan bu algoritmanın etkinliği örnek problemlerle gösterilmiştir.This study presents a hunting search based optimum design algorithm for moment resisting steel frames. Hunting search algorithm is a numerical optimization method inspired by group hunting of animals such as wolves, lions, and dolphins. Each of these hunters performs hunting in a different way. However, they are common in that all of them look for a prey in a group. Prey is encircled and the ring of siege is tightened gradually until it is caught. Hunting search is employed for the automation of optimum design process, during which size variables are selected from an available W-steel section list in such a way that the weight of frame is minimum and the design constraints are satisfied. Provisions of LRFD-AISC (Load and Resistant Factor Design-American Institute of Steel Construction) are considered to formulate the optimum design problem. Different numerical examples are designed by the presented algorithm to demonstrate its efficiency. Results reveal that hunting search shows good performance in finding optimum solutions for moment resisting steel frames

RETIREES FROM PUBLIC SERVICE IN NIGERIA: A SURVEY

The proportion of the Nigeria’s population that is retired is large and growing, and the government face huge fiscal burdens because of promises it has made to provide income security (pension) to this set of people. Improving the adequacy and quality of pension is a priority for Nigerian government, because of the growing disenchantment by retirees over government delays to pay new improved pension schemes. The realization that effective policy and planning must take into account what pensioners want and are prepared to take is the impetus that the government is interested in meaningful life after retirement from public service. The paper aims at enriching our study course on planning for retirement, providing policy makers with reliable basis from the field that are useful for executive decisions, and to enrich would be retirees on what many retirees are experiencing and going through, to plan and save well during work life and to prepare for challenges ahead. Infact, life in retirement is not rosy and cosy for majority as pensioners face difficulties in getting their pays, arrears for months accumulated, government reluctance to implement the 148% increase and several other problems. In protecting the old and promoting economic growth, Nigeria needs to consider comprehensive pension reforms. The research team used direct (contingent valuation) surveys and ML –Censored Normal (Tobit) methods to estimate the number of retirees’ willingness to live meaningful life should the government pay them arrears and implement the increase package and other types of improvement. Clearly, the methodology produced some illuminating in sights into how to decide what level of service is appropriate for this segment of the society and how the improved services should be well implemented

ECB policy and Eurozone fragility: Was De Grauwe right?

Paul De Grauwe's Eurozone fragility hypothesis states that sovereign debt markets in a monetary union without a lender-of-last-resort are vulnerable to self-fulfilling dynamics fuelled by pessimistic investor sentiment that can trigger default. We test this contention by applying an eclectic methodology to a two-year window around Mario Draghi's “whatever-it-takes” pledge that can be understood as the implicit announcement of the Outright Monetary Transactions (OMT) program. A principal components analysis reveals that the perceived commonality in default risk among peripheral and core Eurozone sovereigns increased after the announcement. An event study reveals significant pre-announcement news transmission from Spain to Italy, France, Belgium and Austria that clearly dissipates post-announcement. Country-specific regressions of CDS spreads on systematic risk factors reveal frequent days of large adverse shocks affecting simultaneously those five Eurozone countries, but only during the pre-announcement period. Altogether these findings support the fragility hypothesis and endorse the OMT program

A Flexible Handoff Prioritization Scheme for Improved Quality of Service in Mobile Networks

Efficient handoff prioritization schemes make mobile networks to perform better. However, most existing schemes have the common characteristics of reducing the call drop probability and increasing the call block probability; this decreases the general network performance. The reservation of channels for the use of handoff calls alone has not proved to be an efficient approach to optimally utilize the network limited channel resources. These approaches are such that even when the reserved channels are not in use, new calls could still get blocked if there are no channels among the shared channels to allocate to the new calls. In trying to maintain an improved QoS for handoff calls while ensuring an acceptable QoS for new calls, different methods have been suggested for new calls to access and use the reserved channels while priority is still given to handoff calls since it is more frustrating to have an on-going call dropped than blocking a new call. Network parameters such as call drop probability and traffic intensity had been used separately to determine when new calls could be granted access to use the reserved channels or otherwise. Handoff queuing and other call admission control approaches have also been used. This paper proposes the use of traffic intensity and call drop probability to decide whether the new calls could use the reserved channels or not. Also proposed is the need to keep the number of reserved channels fixed rather than calculating the numbers to reserve per time therefore reducing the computational complexity of the scheme. The simulation results showed an improved QoS for the handoff calls while producing a commensurate improvement for the new calls through a reduced Call drop Probability and call block probability. Keywords: Call block probability, Call drop probability, traffic intensity, handoff prioritization, mobile network DOI: 10.7176/JIEA/11-1-03 Publication date: January 31st 202