Jaehyoun Kim

Managing security and privacy in ubiquitous eHealth information interchange

Ubiquitous computing has the potential to significantly improve the quality of healthcare delivery by making relevant patient health history and vital signs readily available on-demand to caregivers. However, this promise of the ability to track electronic health information signals from distributed ubiquitous devices, conflicts with the security and privacy concerns that most people have regarding their personal information and medical history. While security and privacy concerns have been dealt with extensively in mainstream computing, there is need for new techniques and tools that can enable ubiquitous system designers in healthcare domains to build in appropriate levels of protection. Such techniques can help ensure that patient information is minimally but sufficiently available to different stakeholders in the care giving chain, and are useful in ubiquitous environments where traditional security mechanisms may be either impractical or insufficient. This paper presents a goal-centric and policy-driven framework for deriving security and privacy risk mitigation strategies in ubiquitous health information interchange. Specifically, we use scenario analysis and goal-oriented techniques to model security and privacy objectives, threats, and mitigation strategies in the form of safeguards or countermeasures. We demonstrate that traditional solutions are insufficient, while introducing the notion of purpose-driven security policies based on sensitivity meta-tags. We also show how administrative safeguards (such as those required by HIPAA rules) can be refined into intermediate specifications that can be analyzed more systematically. To validate the utility of our approach, we illustrate our major concepts using examples from ubiquitous emergency response scenarios.

A Design Methodology for Workflow System Development

In every business organization, procedures are established to improve the efficiency, consistency, and quality of work. In this paper, we propose a design methodology for workflow application. It begins with an initial analysis phase (i.e., use case analysis) to capture requirement specifications, and ends with a workflow schema to be executed by a workflow management system. It incorporates workflow technology to support business process modeling that captures business processes as workflow specifications. Also, it employs a multi-step design approach to workflow schema generation, resulting in workflow schema at different levels of abstraction.

Energy-efficient model for guaranteed area coverage in sensor networks with random deployed sensors

One of the main tasks of a wireless sensor network is to provide a necessary level of coverage of their deployment regions. We consider wireless sensor networks where all sensors are independently and uniformly distributed in a finite plane area. We assume that events within the sensing range from some sensor are detectable and the sensor is called to cover that point. In this paper, we investigate a regular coverage model, study how the probability of coverage changes with the sensing range or number of sensors, and formulate an exact mathematical expression for the expected covered ratio. These results allow for determining related parameters (grid size, number of active sensors) for a desired level of sensing coverage.

Verifier-Based home network security mechanism

The home network is expected to experience significant growth over next few years, as wireless and ubiquitous networking becomes more common and accessible. However, the broadcast nature of this technology creates new security issues. To ensure the effective deployment in home environments, network security must reach a certain level which is reasonably acceptable to the research community. The security mechanism for home networks must not require heavy computations, since usually consist of low CPUs capable, limited memory and storage, and mobility concerns. This paper presents a secure authentication and session key establishment mechanism suitable for home networks. The proposed scheme is based on the Secure Remote Password (SRP) protocol. The performance evaluation demonstrates that our proposed mechanism is more secure than previous ones while maintaining the similar level of security overhead including processing time.

Efficient Pre-fetch and Pre-release Based Buffer Cache Management for Web Applications

Various block replacement schemes have been proposed so far to enhance hit ratios by maintaining blocks that will frequently be re-referenced at buffer cache in the future. Especially the LRU block replacement scheme is widely used due to its simplicity and good adaptability to the changes on the working set. However, LRU has a severe drawback that exhibits itself in performance degradation in access patterns with weak locality such as sequential and looping reference. In this paper, we propose an improved LRU buffer cache management scheme using pre-fetching and pre-releasing based on spatial locality. It is as simple as the LRU scheme and retains its characteristics. Trace-driven simulation experiments show that the hit ratios are improved up to about 24% (with the average of 18%) compared to the LRU scheme for the workloads many engineers use.