Naranker Dulay

Naranker Dulay
Imperial College London | Imperial · Department of Computing

About

165
Publications
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Publications

Publications (165)
Preprint
One of the major challenges for the engineering of wireless sensing systems is to improve the software abstractions and frameworks that are available to programmers while ensuring system reliability and efficiency. The distributed systems community have developed a rich set of such abstractions for building dependable distributed systems connected...
Conference Paper
In this abstract we present DejaVu, a 3D virtual world co-simulator for 'visual diffing' of cyber-physical system deployments in indoor and outdoor environments. Using faster-than-real-time simulation and efficient recording DejaVu can record days of simulation data, including environmental, sensor and network data for later replay and analysis. De...
Conference Paper
In this paper we present Ardán, a novel simulation platform using a 3D game engine to stand-in for the real world, providing realistic physics and realistic crowds that can interact in real-time with a cyber-physical simulation. Ardán features 3D device (sensor and actuator) placement, flexible time-control, phenomena-on-demand as well visualisatio...
Conference Paper
In this paper we describe a new approach that uses multi-criteria decision making and the analytic hierarchy process (AHP) for integrating privacy and safety criteria into planning tasks. We apply the approach to the journey planning using two criteria: (i) a willingness-to-share-data (WSD) metric to control data disclosure, and (ii) the number of...
Conference Paper
Short term studies in controlled environments have shown that user behaviour is consistent enough to predict disruptive smartphone notifications. However, in practice, user behaviour changes over time (concept drift) and individual user preferences need to be considered. There is a lack of research on which methods are best suited for predicting di...
Article
This paper is prompted by the overall question 'what is the most effective way to recognise disruptive smartphone interruptions?'. We design our experiments to answer 3 questions: 'Do users revise what they perceive as disruptive incoming calls as time goes by?', 'How do different types of machine-learners (lazy, eager, evolutionary, ensemble) perf...
Article
Access control policies define what resources can be accessed by which subjects and under which conditions. It is, however, often not possible to anticipate all subjects that should be permitted access and the conditions under which they should be permitted. For example, predicting and correctly encoding all emergency and exceptional situations is...
Conference Paper
Mitigating the consequences of disruptive smartphone interruptions remains a challenging problem for smartphone designers. Proposed solutions often incorporate machine-learning techniques with remedies that include delaying user notifications until an opportune moment or changing the intensity and/or mode of the notification (fewer rings, vibration...
Conference Paper
In machine learning, concept drift can cause the optimal solution to a given problem to change as time passes, leading to less accurate predictions. Concept drift can be sudden, gradual or reoccuring. Understanding the consequences of concept drift is particularly important in human-centric applications where changes in the underlying data and envi...
Conference Paper
Home networks are becoming increasingly complex but existing management solutions are not simple to use since they are not tailored to the needs of typical home-users. In this paper we present a new approach to home network management that allows users to formulate quite sophisticated "comic-strip" policies using an attractive iPad application. The...
Article
Full-text available
The advent of mobile and ubiquitous systems has enabled the development of autonomous systems such as wireless-sensors for environmental data collection and teams of collaborating Unmanned Autonomous Vehicles (UAVs) used in missions unsuitable for humans. However, with these range of new application-domains comes a new challenge—enabling self-manag...
Article
Full-text available
As the complexity and size of home networks increases, so does the need for better management support for nonexpert home users. In this paper we describe an extensible policy-based configuration service that allows the home networking infrastructure to be viewed, verified and reconfigured at a higher-level of abstraction. The aim is to ensure that...
Article
Full-text available
Home networks are a fast growing market but managing them is a difficult task, and diagnosing faults is even more challenging. Current fault management tools provide com-prehensive information about the network and the devices but it is left to the user to interpret and reason about the data and experiment in order to find the cause of a prob-lem....
Conference Paper
Full-text available
Location sharing services are becoming increasingly popular. Although many location sharing services allow users to set up privacy policies to control who can access their location, the use made by service providers remains a source of concern. Ideally, location sharing providers and middleware should not be able to access users’ location data with...
Conference Paper
Home networks have evolved to become small-scale versions of enterprise networks. The tools for visualizing and managing such networks are primitive and continue to require networked systems expertise on the part of the home user. As a result, non-expert home users must manually manage non-obvious aspects of the network - e.g., MAC address filterin...
Article
AbstractWith the inclusion of actuators on wireless nodes, Wireless Sensor Networks (WSNs) are starting to change from sense-and-report platforms to sense-and-react platforms. Applications for such platforms are characterised by actuator nodes that are able to react to data collected by sensor nodes. Sensor and actuator nodes use a variety of inter...
Conference Paper
Full-text available
Current security mechanisms are not suitable for organisations that outsource their data management to untrusted servers. Encrypting and decrypting sensitive data at the client side is the normal approach in this situation but has high communication and computation overheads if only a subset of the data is required, for example, selecting records i...
Conference Paper
Experimental evidence from recent measurement studies has shown that bandwidth bottlenecks usually reside at the edges of the Internet, which is also true for residential networks where users share network resources and there is a need to regulate the usage of bandwidth. In this paper we introduce a rule-based approach for specifying bandwidth shar...
Conference Paper
Access control operates under the assumption that it is possible to correctly encode and predict all subjects' needs and rights. However, in human-centric pervasive domains, such as health care, it is hard if not impossible to encode all emergencies and exceptions, but also to imagine a priori all the permissible requests. Break-glass is an approac...
Conference Paper
Event-Condition-Action (ECA) policies are often used to manage various aspects of adaptation and execution of pervasive systems. Such policies are well suited for services where: 1) given actions are reliably executed when they are requested, 2) there is no priority ordering amongst multiple available actions, and 3) execution is instantaneous with...
Conference Paper
Full-text available
The mobile phone offers a unique opportunity to predict a person's behaviour automatically for advanced ubiquitous services. In this note, we analyse cellular data collected as part of the Reality Mining project and use information-theoretic concepts to answer three questions (i) What time points in the day help predict a mobile phone user's activi...
Conference Paper
Policies could potentially be an important and cost-effective technique for building and managing pervasive systems. Historically, policy-based systems have been built using a policy environment that supports the specification and enforcement of policies for a range of management concerns such as adaptation and security. In this short paper we desc...
Conference Paper
In a disaster-recovery mission, rescuers need to coordinate their operations and exchange information to make the right judgments and perform their statutory duties. The information exchanged may be privileged or sensitive and not generally in the public domain. For instance, the assessment of the risk level in the disaster area where a chemical pl...
Article
Full-text available
This paper proposes the architecture for a Self Managed Cell (SMC) for managing both individual and teams of Unmanned Autonomous Vehicles (UXVs). We outline how to specify a mission in terms of roles for UXVs, the tasks to be performed by a role and the policies for managing tasks. A mission specification also includes role assignment policies for...
Conference Paper
Full-text available
The open and dynamic nature of modern distributed systems and pervasive environments presents significant challenges to security management. One solution may be trust management which utilises the notion of trust in order to specify and interpret security policies and make decisions on security-related actions. Most logic-based trust management sys...
Conference Paper
Full-text available
Distributed applications are often built from sets of distributed components that must be co-ordinated in order to achieve some global behaviour. The common approach is to use a centralised controller for co-ordination, or occasionally a set of distributed entities. Centralised co-ordination is simpler but introduces a single point of failure and p...
Article
This paper focuses on the protection of the confidentiality of the data space content when Shared Data Spaces are deployed in open, possibly hostile, environments. In previous approaches, the data space content was protected against access from unauthorised application components by means of access control mechanisms. The basic assumption is that t...
Conference Paper
There is growing interest in using workflows to describe, monitor and direct a wide-range of medical procedures in hospitals. Unlike their well-established business counterparts, medical workflows require a high degree of execution flexibility since it is impossible to anticipate all the possible circumstances that might influence their execution a...
Article
Full-text available
We present a ubiquitous system that combines context information, security mechanisms and a transport infrastructure to provide authentication and secure transport of works of art. Authentication is provided for both auctions and exhibitions, where users can use their own mobile devices to authenticate works of art. Transport is provided by a secur...
Article
Adaptive systems are often composed of distributed components that co-operate in order to achieve a global behaviour, and yet many approaches for adaptive systems are centralised or make strong assumptions about the distributed aspects of the problem. However, if insufficient attention is paid to the problem of decentralisation, especially in the d...
Conference Paper
Full-text available
The increasing complexity of software systems entails large effort to jointly analyze their non-functional attributes in order to identify potential tradeoffs among them (e.g. increased availability can lead to performance degradation). In this paper we propose a framework for the architectural analysis of software performance degradation induced b...
Conference Paper
Pervasive systems are increasingly being designed using a service-oriented approach where services are distributed across wireless devices of varying capabilities. Service orchestration is a simple and popular method to coordinate web-based services but introduces a single point of failure and lacks the flexibility to cope with the greater variabil...
Article
Full-text available
Traffic control is an old and ever growing problem in cities throughout the world. Within many cities, intersections rep-resent bottlenecks in the flow of traffic. Evaluating intersections control is complex and difficult. Given this, intersection manage-ment is both costly and time consuming. This paper considers the potential benefits of enhancin...
Article
Full-text available
A method to determine entry and exit points or paths of DDoS attack traffic flows into and out of network domains is proposed. We observe valid source addresses seen by routers from sampled traffic under non-attack conditions. Under attack conditions, we detect route anomalies by determining which routers have been used for unknown source addresses...
Article
Full-text available
This paper presents a secure distributed management framework for teams of Unmanned Autonomous Vehicles enabling distributed discovery of new team members, authentication and task allocation by any existing team member.
Article
The deployment of Share Data Spaces in open, possible hos- tile, environments arises the need of protecting the confidentiality of the data space content. The approaches that have been proposed focus on access control mechanisms that protect the data space from untrusted agents. The basic assumption is that the hosts (and their administrator) where...
Conference Paper
Full-text available
This dissertation presents a distributed denial-of-service adaptive response (DARE) system, capable of executing appropriate detection and mitigation responses automatically and adaptively according to the attacks. It supports easy integration of distributed modules for both signature-based and anomaly-based detection. Additionally, the innovative...
Conference Paper
In this paper, we present a preliminary design of a framework for coordinating and enforcing usage control policies across different collaborating organisations. We named our framework xDUCON. The main goal of xDUCON is the specification of usage control policies that concisely capture conditions, authorisations, and obligations on both providers a...
Conference Paper
Full-text available
A home network (HN) is usually managed by a user who does not possess knowledge and skills required to perform management tasks. When abnormalities are detected, it is desirable to let the network tune itself under the direction of certain policies. However, self tuning tasks usually require coordination between several network components and most...
Conference Paper
Activity inference attempts to identify what a person is doing at a given point in time from a series of observations. Since the 1980s, the task has developed into a fruitful research field and is now considered a key step in the design of many human-centred systems. For activity inference, wearable and mobile devices are unique opportunities to se...
Conference Paper
Self-managing systems are the focus of an increasing research activity since can provide a more robust way of building software artifacts. In this paper, we focus on self-managing systems for adapting the security concern. Providing security as a one-size-fits-all solution results in a system that is far too rigid to accommodate the needs of differ...
Conference Paper
Full-text available
Determining the time and means by which to travel from location A to location B for a person utilising a MANET requires the dissemination of both realtime and historic data. In this paper, we describe an approach to collecting and analysing the time costs related to geographic tracks, utilising opportunistic networking, local knowledge approximatio...
Conference Paper
Full-text available
Unmanned Autonomous Vehicles (UAVs) are increasingly deployed for missions that are deemed dangerous or impractical to per- form by humans in many military and disaster scenarios. UAVs in a team need to operate in sub-groups or independently to perform specific tasks, but still synchronise state information regularly and cope with intermit- tent co...
Conference Paper
Full-text available
Many missions are deemed dangerous or impractical to perform by humans, but can use collaborating, self-managing unmanned autonomous vehicles (UAVs) which adapt their behaviour to current context, recover from component failure or optimise performance. This paper describes a policy-based distributed self-management framework for both individual and...
Conference Paper
The aim of activity recognition is to identify automatically what a person is doing at a given point in time from a series of observations. Activity recognition is a very active topic and is considered an essential step towards the design of many advanced systems. Mobile and embedded systems have received growing interest as context-sensing platfor...
Conference Paper
Full-text available
Policies form an important part of management and can be an effective means of implementing self-adaptation in pervasive systems. Most policy-based systems focus on large-scale networks and distributed systems. Consequently, they are often fragmented, dependent on infrastructure and lacking flexibility and extensibility. This paper presents Pon- de...
Article
Full-text available
Policy-based management provides the ability to (re-)configure differentiated services networks so that desired Quality of Service (QoS) goals are achieved. This requires implementing network provisioning decisions, performing admission control, and adapting bandwidth allocation to emerging traffic demands. A policy-based approach facilitates flexi...
Conference Paper
In this paper, we present xDUCON a framework for coordinating and enforcing usage control policies across different collaborating organisations. xDUCON allows the specification of usage control policies that concisely capture conditions, authorisations, and obligations on both providers and consumers of resources. The xDUCON framework is based on t...
Conference Paper
In this paper we draw a methodological connection between human routine classification and the sequence alignment problem in bioinformatics. We first observe that human days exhibit important time shifts and therefore align them for comparison prior to classification. Our technique is evaluated on bimodal data including GSM and Bluetooth informatio...
Chapter
This chapter surveys the available specification approaches for security, management, and enterprise collaboration policies. Policies are rules governing the choices in behavior of a system. They are often used as a means of implementing flexible and adaptive systems for management of Internet services, distributed systems, and security systems. Th...
Conference Paper
Body sensor networks (BSNs) have become a promising technology for healthcare, in which biosensors continuously monitor physiological parameters of a user. Distinct from conventional sensor networks for environmental monitoring, such networks need to be adaptive and can therefore be easily managed. In addition, security becomes a necessity. To this...
Conference Paper
The aim of human activity recognition is to identify what a user or a group of users are doing at a given point in time, for example travelling or working. Activity recognition plays an important role in mobile and ubiquitous computing both as a goal in itself and as an intermediate task in the design of advanced applications. Virtually all existin...
Conference Paper
Full-text available
Unmanned Autonomous Vehicles (UAVs) are increasingly deployed for missions that are deemed dangerous or imprac- tical to perform by humans in many military and disas- ter scenarios. Collaborating UAVs in a team form a Self- Managed Cell (SMC) with at least one commander. UAVs in an SMC may need to operate independently or in sub- groups, out of con...
Conference Paper
Full-text available
Body sensor networks (BSNs) for healthcare put more emphasis on security and adaptation to changes in context and application requirement. Policy-based management enables flexible adaptive behaviour by supporting dynamic loading, enabling and disabling of policies without shutting down nodes. This overcomes many of the limitations of sensor operati...
Conference Paper
Sense-and-react applications are characterised by the fact that actuators are able to react to data collected by sensors and change the monitored environment. With the introduction of nodes sporting actuators, Wireless Sensor Networks (WSNs) are being used for realising such applications. Sensor and actuator nodes are capable of interact locally. A...
Article
Full-text available
The era of pervasive computing brings with it a grand challenge: Pervasive applications must adapt to the dynamics entailed in human behavior and constantly changing computing environments. In this paper, we propose Adaptable Pervasive Flows as a novel technology that goes far beyond existing approaches for adapting pervasive computing systems. APF...
Conference Paper
Full-text available
Managing security in distributed systems requires flexible and expressive authorisation models with support for conflict resolution. Models need to be hierarchical but also non-monotonic supporting both positive and negative authorisations. In this paper, we present an approach to resolve the authorisation conflicts that inevitably occur in such mo...
Conference Paper
Full-text available
Policy-based management enables flexible adaptive behaviour by supporting dynamic loading, enabling and disabling of policies without shutting down nodes. This overcomes many of the limitations of sensor node operating systems, such as TinyOS, which do not support dynamic modification of code. This paper presents the design, implementation and eval...
Conference Paper
Policies form an important part of management activities and are an effective means of implementing self-adaptation in pervasive systems. Many policy- based systems designed to date focus on large-scale networks and distributed systems. Consequently, they are often fragmented, dependent on infrastructure and lacking flexibility and extensibility. T...
Conference Paper
Full-text available
In this paper, we describe a new framework for healthcare systems where patients are able to control the disclosure of their medical data. In our framework, the patient's consent has a pivotal role in granting or removing access rights to subjects accessing patient's medical data. Depending on the context in which the access is being executed, diff...
Conference Paper
The deployment of Share Data Spaces in open, possibly hos- tile, environments arises the need of protecting the confidentiality of the data space content. Existing approaches focus on access control mecha- nisms that protect the data space from untrusted agents. The basic as- sumption is that the hosts (and their administrators) where the data spac...
Conference Paper
Full-text available
A method to determine entry points and paths of DDoS attack traffic flows into network domains is proposed. We determine valid source addresses seen by routers from sampled traffic under non-attack conditions. Under attack conditions, we detect route anomalies by determining which routers have been used for unknown source addresses to construct the...
Conference Paper
Full-text available
In this paper, we present a framework where access rights are provided to entities on the basis of the actual task that the entities must fulfill as part of their duties. For capturing the requirements of entities' duties we use the notion of workflow. Our main aim is to provide an access control mechanism that is able to balance the competing goal...
Article
Future e-Health systems will consist of low-power on-body wireless sensors attached to mobile users that interact with an ubiquitous computing environment to monitor the health and well being of patients in hospitals or at home. Patients or health practitioners have very little technical computing expertise so these systems need to be self-configur...
Article
Full-text available
This paper describes a reconfigurable architecture based on field-programmable gate-array (FPGA) technology for monitoring and analyzing network traffic at increasingly high network data rates. Our approach maps the performance-critical tasks of packet classification and flow monitoring into reconfigurable hardware, such that multiple flows can be...
Conference Paper
Today's high-end mobile phones commonly include one or two digital cameras. These devices, also known as cameraphones, allow their owners to take photographs anywhere, at any time with practically no cost. As a result, many urban dwellers are photographed everyday without even being aware of it. Although in many countries, legislation recognises th...
Conference Paper
Middleware-based solutions for self-managing systems pro- vide a degree of separation between the mechanisms that govern the adaptability of a system and application func- tionality. Systems become in this way more ∞exible, de- pendable and robust to changes. However, it is possible to achieve another degree of separation by separating from the app...
Conference Paper
Context datasets are essential not only to design and evaluate context-aware systems but also to help identify important problems. For practical and ethical reasons, collecting real-life context data is not always feasible. In this paper, we investigate the possibility to use context data extracted from screenplays in certain context-aware applicat...