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This paper presents an overview of some of the technical and managerial aspects of protecting the personnel, data processing systems and computer facility from deliberate or accidental damage by internal or external forces.With regard to site planning, the environmental compatibility between the computer system, its data communication and electric energy systems must be established. Electro-magnetic spectrum area profiles are utilized to detect high energy transmitters which could necessitate shielding of the facility and filtering of all incoming wire lines. The effects of magnetic fields on magnetic storage media is also discussed.The unique requirements of real-time, on-line systems, i.e. airline reservation, satellite tracking, require special solutions related to uniterruptable power systems (UPS). In this context this paper will also examine the management decisions which must be made regarding the cost effectiveness of a "fail safe" vs "fail soft" system.Data security is examined in light of the time-value relationship of information applied to programming changes, data transmission to remote terminals, available software and hardward cryptography systems.The application of various electro mechanical devices and computing systems for use in area control situations is examined. Additionally, the relatively new use of voice, hand and fingerprints for access control is surveyed.The use of closed circuit television and its effect on personnel management will also be considered. Low light level techniques and time-lapse video tape recording sub systems applied to unmanned surveillance of critical areas or processes is discussed.

Since mobile code can migrate from a remote site to a host and can interact with the resources and facilities of the host, security becomes the key to the success of mobile code computation. Existing mobile code security mechanisms such as access control are not able to fully address the import security properties of the host including confidentiality and integrity. And these practices tend to protect the host from potential attacks by confining the mobile code, thus will impair the function of mobile code. Information-flow policy is a technique that can ensure confidentiality, however the analysis of the information flow is practically difficult. This paper describes an innovative approach to provide Java mobile code system security by bytecode analysis. The key technique of the approach is the dependence analysis adapted to information flow analysis. A security model for mobile code system is also proposed in this paper. By this approach, two major properties of the host security– integrity and confidentiality can be protected while the additional restriction on mobile code can be greatly avoided. A prototype has been implemented, which can be applied to analyze Java class file, applet and mobile agent.

This paper describes the design of mechanisms to control sharing of information in the Multics system. Seven design principles help provide insight into the tradeoffs among different possible designs. The key mechanisms described include access control lists, hierarchical control of access specifications, identification and authentication of users, and primary memory protection. The paper ends with a discussion of several known weaknesses in the current protection mechanism design.

The design of mechanisms to control the sharing of information in the Multics system is described. Five design principles help provide insight into the tradeoffs among different possible designs. The key mechanisms described include access control lists, hierarchical control of access specifications, identification and authentication of users, and primary memory protection. The paper ends with a discussion of several known weaknesses in the current protection mechanism design.

This paper is concerned with ramp control which is responsive to freeway incidents. The object considered is to optimize (minimize) a weighted combination of affected freeway and diverted vehicles. The model of queue dynamics used was developed in earlier related work and is outlined here. The control law that results is an extremum solution (ramp completely open or completely closed), with the decision dependent upon the weight given diverted vehicles and upon macroscopic system parameters. Consideration is given to the case where complete closure is prohibited. The extension to partial blockages on multi-lane facilities is discussed.

Protection of computations and information is an important aspect of a computer utility. In a system which uses segmentation as a memory addressing scheme, protection can be achieved in part by associating concentric rings of decreasing access privilege with a computation. This paper describes hardware processor mechanisms for implementing these rings of protection. The mechanisms allow cross-ring calls and subsequent returns to occur without trapping to the supervisor. Automatic hardware validation of references across ring boundaries is also performed. Thus, a call by a user procedure to a protected subsystem (including the the supervisor) is identical to a call to a companion user procedure. The mechanisms of passing and referencing arguments are the same in both cases as well.

This paper is concerned with an investigation of the feasible track-density potential of random-access magnetic-disk storage where magnetic-head positioning is essential. Primary emphasis is given to a novel, servo-access concept (closed-looped head-positioning control which includes the record member) for track location and registration. This servo concept has been investigated as a means of making possible automatic tracking as well as precision positioning. Inherent in such an access control technique is an enhanced suitability for interchangeable record members. Included in the discussion are design and performance results of an access model operated at 154 tracks per inch.

Security in today's government and commercial environments is changing. The willingness to provide manpower against security threats is diminishing. Risk management is preferred to risk avoidance. In order for management to ensure that the appropriate security is provided while downsizing or right sizing protective services and other security personnel, automation of security technologies is a necessity. Several manpower intensive tasks and processes are: facilities access control, issuance of staff and visitor badges, provision of information for visitors, access control to interior facilities, and the issuance of office keys. Reduction of the required manning for these processes is enabled though the automation and integration of various security technologies including biometric identification systems. This paper provides a background on manpower intensive tasks and processes, security technologies that may be employed within them, resource reduction capabilities, and a customer's experience with the use of the technologies within a large Government environment.

This paper presents a model for engineering the user interface for large data base systems in order to maintain flexible access controls over sensitive data. The model is independent of both machine and data base structure, and is sufficiently modular to allow cost-effectiveness studies on access mechanisms. Access control is based on sets of procedures called formularies. The decision on whether a user can read, write, update, etc., data is controlled by programs (not merely bits or tables of data) which can be completely independent of the contents or location of raw data in the data base.

This paper describes an experiment in which seven relevance feedback document retrieval techniques are compared. It is shown that for the set of parameters and indexed document collection used, two of the techniques performed worse than the initial queries and that the greatest gains in precision for the others occur at low levels of recall. At the extreme recall levels no significant differences were found among any of the techniques while over all recall levels no significant differences were found among five of the techniques.