738 research outputs found
High Resolution X-Ray CT for Advanced Electronics Packaging
Advanced electronics packaging is a challenge for non-destructive Testing (NDT). More, smaller and mostly hidden interconnects dominate modern electronics components and systems. To solve the demands of customers to get products with a high functionality by low volume, weight and price (e.g. mobile phones, personal medical monitoring systems) often the designers use System-in-Package solutions (SiP). The non-destructive testing of such devices is a big challenge (see [1]). So our paper will impart fundamentals and applications for non-destructive evaluation of inner structures of electronics packaging for quality assurance and reliability investigations.
The main NDE methods for electronics packaging are scanning acoustic microscopy and X-ray macrostructure analysis like X-ray radiography and X-ray computed tomography (CT) (see [2] & [3]). Our presentation will focus on X-ray nano focus computed tomography as a method for component development, process development and reliability research. We will discuss the potentials and the limits of X-ray NDE techniques, illustrated by crack observation in solder joints, evaluation of micro vias in PCBs and interposers and the investigation of a complex SiP like a USB memory device. We will show tomography results with voxel sizes less than 800nm. To reach these results we developed special techniques to prepare the samples for high resolution CTs. Figure 1 shows the tool, a prepared specimen and a high resolution CT result picture
n-representation infinite algebras
From the viewpoint of higher dimensional Auslander-Reiten theory, we introduce a new class of finite dimensional algebras of global dimension n, which we call n-representation infinite. They are a certain analog of representation infinite hereditary algebras, and we study three important classes of modules: n-preprojective, n-preinjective and n-regular modules. We observe that their homological behaviour is quite interesting. For instance they provide first examples of algebras having infinite Ext 1-orthogonal families of modules. Moreover we give general constructions of n-representation infinite algebras. Applying Minamoto’s theory on Fano algebras in non-commutative algebraic geometry, we describe the category of n-regular modules in terms of the corresponding preprojective algebra. Then we introduce n-representation tame algebras, and show that the category of n-regular modules decomposes into the categories of finite dimensional modules over localizations of the preprojective algebra. This generalizes the classical description of regular modules over tame hereditary algebras. As an application, we show that the representation dimension of an n-representation tame algebra is at least n+2
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A comparative study of Oregon and New Zealand as tourist destinations : tourism resources, perceptions, and travel patterns
Tourism has become an important factor in Oregon's and
New Zealand's economies. Both destinations are trying to
attract even more tourists. However, many other destinations
are also competing for a bigger share of the tourism market.
Tourism itself is a multi-faceted phenomenon and the travel
destination decision is of some importance, not only for the
person but also for the tourist destinations. A Travel
Destination Decision Model was developed which integrates the
most important aspects of the decision process. The purpose
of this study was to examine relationships between some of
these facets: tourism resources, perceptions, and travel
patterns. It was hypothesized that: (A) a quantitatively and
qualitatively better resource base results in a more
favorable perception; (B) similar resource bases may still
result in different perceptions; and (C) similar perceptions
result in similar travel patterns and a more favorable
perception results in a higher volume of travel flow.
A literature survey provided information on the tourism
resource base and travel flow of both destinations. Data on
the perceptions of both destinations were obtained through a survey at Frankfurt airport, Federal Republic of Germany. The
sample population of this self-administered questionnaire was
356 persons of international origin.
Hypotheses (A) and (B) were verified by the results of
this sample population for the destinations Oregon and New
Zealand. Hypothesis (C) was not supported for Oregon and New
Zealand. This was attributed to their respective geographical
locations and therewith induced factors such as cost, time,
and accessibility. A test of hypothesis (C) for the
relatively similar located states Oregon and California
supported this assumption, as hypothesis (C) was verified for
these destinations
An SU(5) x A5 Golden Ratio Flavour Model
In this paper we study an SU(5) x A5 flavour model which exhibits a neutrino
mass sum rule and golden ratio mixing in the neutrino sector which is corrected
from the charged lepton Yukawa couplings. We give the full renormalizable
superpotential for the model which breaks SU(5) and A5 after integrating out
heavy messenger fields and minimising the scalar potential. The mass sum rule
allows for both mass orderings but we will show that inverted ordering is not
valid in this setup. For normal ordering we find the lightest neutrino to have
a mass of about 10-50 meV, and all leptonic mixing angles in agreement with
experiment.Comment: 34 pages, 5 figures; version published in Nucl. Phys.
The multimedia challenges raised by pervasive games
Pervasive gaming is a new form of multimedia entertainment that extends the traditional computer gaming experience out into the real world. Through a combination of personal devices, positioning systems and other multimedia sensors, combined with wireless networking, a pervasive game can respond to a player’s movements and context and enable them to communicate with a game server and other players. We review recent examples of pervasive games in order to explain their distinctive characteristics as multimedia applications. We then consider the challenge of scaling pervasive games to include potentially very large numbers of players. We propose a new approach based upon a campaign model in which individuals, local groups and experts draw on a combination of pervasive games, online services and broadcasting to take part in national or even global events. We discuss the challenges that this raises for further researc
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