Generic Architecture and Semiconductor Intellectual Property Cores for Avanced Encryption Standard Cryptography

A generic architecture for implementing the advanced encryption standard (AES) encryption algorithm in silicon is proposed. This allows the instantiation of a wide range of chip specifications, with these taking the form of semiconductor intellectual property (IP) cores. Cores implemented from this architecture can perform both encryption and decryption and support four modes of operation: (i) electronic codebook mode; (ii) output feedback mode; (iii) cipher block chaining mode; and (iv) ciphertext feedback mode. Chip designs can also be generated to cover all three AES key lengths, namely 128 bits, 192 bits and 256 bits. On-the-fly generation of the round keys required during decryption is also possible. The general, flexible and multi-functional nature of the approach described contrasts with previous designs which, to date, have been focused on specific implementations. The presented ideas are demonstrated by implementation in FPGA technology. However, the architecture and IP cores derived from this are easily migratable to other silicon technologies including ASIC and PLD and are capable of covering a wide range of modem communication systems cryptographic requirements. Moreover, the designs produced have a gate count and throughput comparable with or better than the previous one-off solutions.

Towards agent-oriented model-driven architecture

Model Driven Architecture supports the transformation from reusable models to executable software. Business representations, however, cannot be fully and explicitly represented in such models for direct transformation into running systems. Thus, once business needs change, the language abstractions used by MDA (e.g. Object Constraint Language / Action Semantics), being low level, have to be edited directly. We therefore describe an Agent-oriented Model Driven Architecture (AMDA) that uses a set of business models under continuous maintenance by business people, reflecting the current business needs and being associated with adaptive agents that interpret the captured knowledge to behave dynamically. Three contributions of the AMDA approach are identified: 1) to Agent-oriented Software Engineering, a method of building adaptive Multi-Agent Systems; 2) to MDA, a means of abstracting high level business-oriented models to align executable systems with their requirements at runtime; 3) to distributed systems, the interoperability of disparate components and services via the agent abstraction.

Implementing a resuscitation policy for patients at the end of life in an acute hospital setting: qualitative study

Objective : To explore attitudes and experiences of doctors and nurses regarding cardiopulmonary resuscitation for patients with end stage illness in an acute hospital. Design : Qualitative study; thematic analysis of two audio-taped focus groups and four semi-structured interviews. Setting : Acute district hospital, Northern Ireland. Participants : Seven nurses and nine doctors; varying nationality, gender and years of professional experience; involved in cardiopulmonary resuscitation decision-making. Results : Participants reported different interpretations of resuscitation policy and of what do not attempt to resuscitate (DNAR) decisions meant in relation to practical care for patients. This confusion in translating policy into practice contributed to communication difficulties in initiating, documenting and implementing cardiopulmonary resuscitation decisions. Participants were aware of how clinical conditions could change and reported uncertainty in determining end stage illness; they expressed fears of potential consequences of DNAR decisions for patients' care. The more disease-centred approach of doctors to patients' management, compared to nurses' more patient-centred approach, contributed to inter-professional conflict within teams. Doctors identified training needs in applying resuscitation policy and ethical principles in `real life' and nurses identified a need for ongoing professional support, which was perceived as being less available to junior doctors. Personal relationships between staff and patients, cultural reluctance to address sensitive issues and local community expectations of relatives being involved in decisions added to policy implementation difficulties. Conclusions : The findings indicate a need for ongoing staff support and training in applying resuscitation policy to decisions for patients with end stage illness in an acute hospital. They support suggestions that reviews of local resuscitation policy and of national guidelines should be undertaken with openness and honesty regarding the goals, opportunities and difficulties involved in trying to deliver good end of life care in local settings. Palliative Medicine 2007; 21 : 305—312 Key Words: do not attempt resuscitation (DNAR) • end stage illness • inter-professional • policy • resuscitation decisions