365 research outputs found
How Effective is China’s Monetary Policy? An assessment of the link between the growth of monetary aggregates and inflation during the 2000s
The effectiveness of China’s monetary policy hinges on the existence of a robust link between the growth of monetary aggregates and inflation. This paper considers this link during the 2000s using Structural VAR models and simulated out-of-sample forecasting techniques. The results indicate that the link is far from robust. Such findings serve to underscore the importance of institutional reforms that will enable interest rates to play a more prominent role as an instrument of monetary policy.
Orbital transfer vehicle concept definition and system analysis study, 1985. Volume 3: System and program trades
The key system and program trade studies performed to arrive at a preferred Orbital Transfer Vehicle (OTV) system concept and evolutionary approach to the acquisition of the requisite capabilites is documented. These efforts were expanded to encompass a Space Transportation Architecture Study (STAS) mission model and recommended unmanned cargo vehicle. The most important factors affecting the results presented are the mission model requirements and selection criteria. The reason for conducting the OTV concept definition and system analyses study is to select a concept and acquisition approach that meets a delivery requirement reflected by the mission model
Improving responsiveness of Android activity navigation via genetic improvement
Responsiveness issues are one of the key reasons why mobile phone users abandon an app or leave bad reviews. In this work, we explore the use of Genetic Improvement to automatically refactor applications to reduce the time taken to move between and within Android activities, without affecting their functionality. This particular Android responsiveness issue has not previously been tackled before. With its application directly to source code, our approach can be used to complement previous work, which modifies the operating system, or focuses on detection of specific coding patterns. We present a fully automated technique for finding improvements to this responsiveness, which does not require the use of an Android device or emulator. We apply our approach to 7 real-world open source applications and find improvements of up to 30% in navigation response time
Multi-Objective Improvement of Android Applications
Non-functional properties, such as runtime or memory use, are important to
mobile app users and developers, as they affect user experience. Previous work
on automated improvement of non-functional properties in mobile apps failed to
address the inherent trade-offs between such properties. We propose a practical
approach and the first open-source tool, GIDroid (2023), for multi-objective
automated improvement of Android apps. In particular, we use Genetic
improvement, a search-based technique that navigates the space of software
variants to find improved software. We use a simulation-based testing framework
to greatly improve the speed of search. GIDroid contains three state-of-the-art
multi-objective algorithms, and two new mutation operators, which cache the
results of method calls. Genetic improvement relies on testing to validate
patches. Previous work showed that tests in open-source Android applications
are scarce. We thus wrote tests for 21 versions of 7 Android apps, creating a
new benchmark for performance improvements. We used GIDroid to improve versions
of mobile apps where developers had previously found improvements to runtime,
memory, and bandwidth use. Our technique automatically re-discovers 64% of
existing improvements. We then applied our approach to current versions of
software in which there were no known improvements. We were able to improve
execution time by up to 35%, and memory use by up to 33% in these apps.Comment: 32 pages, 8 Figure
Magnetic Monopoles in String Theory
Magnetic monopole solutions to heterotic string theory are discussed in
toroidal compactifications to four spacetime dimensions. Particular emphasis is
placed on the relation to previously studied fivebrane solutions in ten
dimensions and on the possibility of constructing exact monopole solutions
related to symmetric fivebranes.Comment: 24 pages (Corrected title
Orbital transfer vehicle concept definition and system analysis study, 1985. Volume 5: Work breakdown structure and dictionary
To establish consistency and visibility within the Orbital Transfer Vehicle (OTV) program, a preliminary work breakdown structure (WBS) and dictionary were developed. The dictionary contains definitions of terms to be used in conjunction with the WBS so that a clear understanding of the content of the hardware, function, and cost elements may be established. The OTV WBS matrix is a two-dimensional structure which shows the interrelationship of these dimensions: the hardware elements dimension and the phase and function dimension. The dimension of time cannot be shown graphically, but must be considered. Each cost entry varies with time so that it is necessary to know these cost values by year for budget planning and approval as well as for establishing cost streams for discounting purposes in the economic analysis. While a multiple dimensional approach may at first appear complex, it actually provides benefits which outweigh any concern. This structural interrelationship provides the capability to view and analyze the OTV costs from a number of different financial and management aspects. Cost may be summed by hardware groupings, phases, or functions. The WBS may be used in a number of dimensional or single listing format applications
How Do Android Developers Improve Non-Functional Properties of Software?
Nowadays there is an increased pressure on mobile app developers to take non-functional properties into account. An app that is too slow or uses much bandwidth will decrease user satisfaction, and thus can lead to users simply abandoning the app. Although automated software improvement techniques exist for traditional software, these are not as prevalent in the mobile domain. Moreover, it is yet unknown if the same software changes would be as effective. With that in mind, we mined overall 100 Android repositories to find out how developers improve execution time, memory consumption, bandwidth usage and frame rate of mobile apps. We categorised non-functional property (NFP) improving commits related to performance to see how existing automated software improvement techniques can be improved. Our results show that although NFP improving commits related to performance are rare, such improvements appear throughout the development lifecycle. We found altogether 560 NFP commits out of a total of 74,408 commits analysed. Memory consumption is sacrificed most often when improving execution time or bandwidth usage, although similar types of changes can improve multiple non-functional properties at once. Code deletion is the most frequently utilised strategy except for frame rate, where increase in concurrency is the dominant strategy. We find that automated software improvement techniques for mobile domain can benefit from addition of SQL query improvement, caching and asset manipulation. Moreover, we provide a classifier which can drastically reduce manual effort to analyse NFP improving commits
Born-Regulated Gravity in Four Dimensions
Previous work involving Born-regulated gravity theories in two dimensions is
extended to four dimensions. The action we consider has two dimensionful
parameters. Black hole solutions are studied for typical values of these
parameters. For masses above a critical value determined in terms of these
parameters, the event horizon persists. For masses below this critical value,
the event horizon disappears, leaving a ``bare mass'', though of course no
singularity.Comment: LaTeX, 15 pages, 2 figure
POVERTY AND TIME: PERSPECTIVES ON THE DYNAMICS OF POVERTY. General Research Series Paper No. 166, December 1994
The ESRI’s 1987 Survey of Income Distribution, Poverty and Use of
State Services has served as the basis for a lengthy series of studies of
poverty and related topics in Ireland. The present study extends that
research by exploiting the wealth of data in the survey), which can throw
light on the dynamics of resources, income and poverty. To understand why
some people are trapped in poverty while others escape from it, why low income has a much more immediate impact on living standards for some
households than others, and why some people are at much higher risk of
poverty than others, one needs to look at socio-economic background,
acquisition of education and skills, labour market experiences, and the
build-up of savings versus debts over a long period. By doing so, our
understanding of poverty and how best to design anti-poverty policy is
significantly enhanced
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