M. A. C. Dekker

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We describe a policy language and implement its associated proof checking system. In our system, agents can distribute data along with usage policies in a decentralized architecture. Our language supports the specification of conditions and obligations, and also the possibility to refine policies. In our framework, the compliance with usage policies is not(More)
Traditional access control mechanisms aim to prevent illegal actions a-priori occurrence, i.e. before granting a request for a document. There are scenarios however where the security decision can not be made on the fly. For these settings we developed a language and a framework for a-posteriori access control. In this paper we show how the framework can be(More)
In this paper we introduce a new framework for controlling compliance to discretionary access control policies [Cederquist et al. in Proceedings of the International Workshop on Policies for Distributed Systems and Networks (POLICY), 2005; Corin et al. in Proceedings of the IFIP Workshop on Formal Aspects in Security and Trust (FAST), 2004]. The framework(More)
We present a distributed framework where agents can share data along with usage policies. We use an expressive policy language including conditions, obligations and delegation. Our framework also supports the possibility to refine policies. Policies are not enforced a-priori. Instead policy compliance is checked using an a-posteriri auditing approach.(More)
Medical and psychosocial problems related to substance use disorders (SUDs) remain a major source of national morbidity and mortality. This situation exists despite greater understanding of genetic, neurobiologic, and social underpinnings of the development of these illnesses that has resulted in many advances in addiction medicine. The value of assessment(More)
Substance use disorders (SUDs) have had a major impact on the health of the US population during the past decade. Osteopathic physicians have an important role among those who can make a positive impact on this problem. This article reviews the nature of the problem, how the osteopathic medical profession is currently addressing it, and a current strategy(More)
BACKGROUND A new class of synthetic hallucinogens called NBOMe has emerged as drugs of abuse. OBJECTIVE Our aim was to conduct a systematic review of published reports of toxicities associated with NBOMe ingestion. METHODS We searched PubMed for relevant English-language citations that described adverse effects from analytically confirmed human NBOMe(More)
Large and distributed access control systems are increasingly common, for example in health care. In such settings, access control policies may become very complex, thus complicating correct and efficient adminstration of the access control system. Despite being one of the most widely used access control standards, RBAC does not include an administration(More)
In existing RBAC literature, administrative privileges are inherited just like ordinary user privileges. We argue that from a security viewpoint this is too restrictive, and we believe that a more flexible approach can be very useful in practice. We define an ordering on the set of administrative privileges, enabling us to extend the standard privilege(More)
Flexibility of management is an important requisite for access control systems as it allows users to adapt the access control system in accordance with practical requirements. This paper builds on earlier work where we defined administrative policies for a general class of RBAC models. We present a formal definition of administrative refinement and we show(More)