68,072 research outputs found
Sliding Mode Control of Two-Level Quantum Systems
This paper proposes a robust control method based on sliding mode design for
two-level quantum systems with bounded uncertainties. An eigenstate of the
two-level quantum system is identified as a sliding mode. The objective is to
design a control law to steer the system's state into the sliding mode domain
and then maintain it in that domain when bounded uncertainties exist in the
system Hamiltonian. We propose a controller design method using the Lyapunov
methodology and periodic projective measurements. In particular, we give
conditions for designing such a control law, which can guarantee the desired
robustness in the presence of the uncertainties. The sliding mode control
method has potential applications to quantum information processing with
uncertainties.Comment: 29 pages, 4 figures, accepted by Automatic
A Generic Storage API
We present a generic API suitable for provision of highly generic storage
facilities that can be tailored to produce various individually customised
storage infrastructures. The paper identifies a candidate set of minimal
storage system building blocks, which are sufficiently simple to avoid
encapsulating policy where it cannot be customised by applications, and
composable to build highly flexible storage architectures. Four main generic
components are defined: the store, the namer, the caster and the interpreter.
It is hypothesised that these are sufficiently general that they could act as
building blocks for any information storage and retrieval system. The essential
characteristics of each are defined by an interface, which may be implemented
by multiple implementing classes.Comment: Submitted to ACSC 200
On Integrating Student Empirical Software Engineering Studies with Research and Teaching Goals
Background: Many empirical software engineering studies use students as subjects and are conducted as part of university courses. Aim: We aim at reporting our experiences with using guidelines for integrating empirical studies with our research and teaching goals. Method: We document our experience from conducting three studies with graduate students in two software architecture courses. Results: Our results show some problems that we faced when following the guidelines and deviations we made from the original guidelines. Conclusions: Based on our results we propose recommendations for empirical software engineering studies that are integrated in university courses.
When Cost-Efficient Technologies Meet Politics: A Case Study of Radical Wireless Network Implementation
Cost efficiency has been a dominant perspective in the traditional IT literature. However, in complex technology and business environment, the widely recognized cost efficient assumption of information technology has been increasingly challenged. Drawing from a case study of wireless network implementation situated in a politically sensitive workplace, this paper provided practice insights for IT managers in today’s networked economy. More specifically, stories experienced in the case study illustrated that despite well-calculated cost efficiency of wireless network infrastructure, the radical implementation process in the case organization encountered enormous challenges and opposition due to the fact that administrators failed to consider various stakeholders’ positions and interests. Eventually, the implementation objectives and outcome were considerably undermined. Implications from this empirical case research reemphasized the significance of understanding political forces situated in any business environment where different stakeholders hold conflicting interests. Lessons learned from the case story further encouraged IT managers and policy makers to better strategize emerging information technology in general and wireless networks in particular as the whole
global society and business environment are increasingly facing an emerging wireless world
Ubiquitous computing and knowledge management
MOBIlearn is a large European research project to develop a mobile learning system to facilitate formal, non formal and informal learning. The project has two primary objectives: • Develop a methodology for creating mobile learning scenarios and producing learning objects to implement them. • Develop the technology to deliver the learning objects to users via mobile computing devices. This paper will concentrate the MOBIlearn health care domain. One of this applications main objectives is managing and sharing of tacit knowledge. Using the system participants discuss case studies
and alternative approaches to specific problems are evaluated and documented. This is then used and extended in future case studies. In a mobile learning environment, individual health workers can use the system to either advanced their skills, or in a ‘live’ incident, use it for reference and indeed call for backup.</p
Accelerating positive change in electronic records management: an empirical toolkit of solutions
The AC+erm project aims to investigate and critically explore issues and practical strategies for accelerating positive change in electronic records management. The project’s focus is on designing an organisational-centred architecture from three perspectives: people, process and technology. This paper introduces the project, describes the methodology (a systematic literature review, e-Delphi studies and colloquia) and presents solutions for improving ERM developed from the people and process e-Delphi responses. ERM is particularly challenging and the solutions offered by the Delphi participants are numerous, and range in scale and complexity. The only firm conclusion that one can draw is that the majority of the solutions are people-focussed ones. The Cynefin framework is introduced as one approach for providing a conceptual overview to our findings on ERM. The sample solutions presented in this paper provide a toolkit of ‘probes’ and ‘interventions’ for practical application in organisations
X-Vine: Secure and Pseudonymous Routing Using Social Networks
Distributed hash tables suffer from several security and privacy
vulnerabilities, including the problem of Sybil attacks. Existing social
network-based solutions to mitigate the Sybil attacks in DHT routing have a
high state requirement and do not provide an adequate level of privacy. For
instance, such techniques require a user to reveal their social network
contacts. We design X-Vine, a protection mechanism for distributed hash tables
that operates entirely by communicating over social network links. As with
traditional peer-to-peer systems, X-Vine provides robustness, scalability, and
a platform for innovation. The use of social network links for communication
helps protect participant privacy and adds a new dimension of trust absent from
previous designs. X-Vine is resilient to denial of service via Sybil attacks,
and in fact is the first Sybil defense that requires only a logarithmic amount
of state per node, making it suitable for large-scale and dynamic settings.
X-Vine also helps protect the privacy of users social network contacts and
keeps their IP addresses hidden from those outside of their social circle,
providing a basis for pseudonymous communication. We first evaluate our design
with analysis and simulations, using several real world large-scale social
networking topologies. We show that the constraints of X-Vine allow the
insertion of only a logarithmic number of Sybil identities per attack edge; we
show this mitigates the impact of malicious attacks while not affecting the
performance of honest nodes. Moreover, our algorithms are efficient, maintain
low stretch, and avoid hot spots in the network. We validate our design with a
PlanetLab implementation and a Facebook plugin.Comment: 15 page
Overview of Hydra: a concurrent language for synchronous digital circuit design
Hydra is a computer hardware description language that integrates several kinds of software tool (simulation, netlist generation and timing analysis) within a single circuit specification. The design language is inherently concurrent, and it offers black box abstraction and general design patterns that simplify the design of circuits with regular structure. Hydra specifications are concise, allowing the complete design of a computer system as a digital circuit within a few pages. This paper discusses the motivations behind Hydra, and illustrates the system with a significant portion of the design of a basic RISC processor
The Evolution of Embedding Metadata in Blockchain Transactions
The use of blockchains is growing every day, and their utility has greatly
expanded from sending and receiving crypto-coins to smart-contracts and
decentralized autonomous organizations. Modern blockchains underpin a variety
of applications: from designing a global identity to improving satellite
connectivity. In our research we look at the ability of blockchains to store
metadata in an increasing volume of transactions and with evolving focus of
utilization. We further show that basic approaches to improving blockchain
privacy also rely on embedding metadata. This paper identifies and classifies
real-life blockchain transactions embedding metadata of a number of major
protocols running essentially over the bitcoin blockchain. The empirical
analysis here presents the evolution of metadata utilization in the recent
years, and the discussion suggests steps towards preventing criminal use.
Metadata are relevant to any blockchain, and our analysis considers primarily
bitcoin as a case study. The paper concludes that simultaneously with both
expanding legitimate utilization of embedded metadata and expanding blockchain
functionality, the applied research on improving anonymity and security must
also attempt to protect against blockchain abuse.Comment: 9 pages, 6 figures, 1 table, 2018 International Joint Conference on
Neural Network
- …