Personal computer

About: Personal computer is a research topic. Over the lifetime, 58809 publications have been published within this topic receiving 800814 citations. The topic is also known as: PC.

System and method for conducting cashless transactions on a computer network

Abstract: In a commercial transaction system, a system user uses a personal computer to interact with merchant computers over the Internet to conduct cashless transactions. Each system user computer processes data including a balance stored in the computer's memory and updates the stored data at the end of the transaction. The system is specially designed for purchases of items or transactions of relatively small monetary value. In this manner, the amount of the transaction is deducted from the balance on the computer. In accordance with the invention, when the existing balance associated with the computer does not cover the price of the transaction, the system provides a reload feature which gives the user an option to increase the balance of the computer. Such a feature allows the purchase to be made without inconveniencing the user to increase the balance by other means. Each time the balance is increased by a reload, the user's issuer bank bills the user for the reload amount.

Modified Butterworth-Van Dyke circuit for FBAR resonators and automated measurement system

Abstract: Microwave Film Bulk Acoustic Resonators (FBARs) may be characterized by means of the Mason transmission line model, but for parameter extraction and design studies, the lumped Butterworth-Van Dyke (BVD) model is more useful. We propose a modification to the standard five element BVD model, in which a second resistor is added in series with the plate capacitance C/sub 0/. This improves the model predictions as compared to the data obtained from a network analyzer (NWA). Here, the modified model will be developed in terms of the resonant frequencies, effective coupling constant k/sub t//sup 2/, and the quality factor Q, as determined from the S parameters of an FBAR measured by the NWA. To evaluate the FBAR resonators on a routine basis, an automated data acquisition and parameter extraction method based on the Modified Butterworth-Van Dyke model (MBVD) is described. An Agilent Technologies 8753ES NWA operating under Personal Computer control is used to acquire and process FBAR data by means of a custom HPVEE/sup TM/ program, which transfers data from the NWA, and extracts the six MBVD circuit parameters. Excellent agreement is obtained between the measured data for a typical FBAR resonator and calculated "postdictions" obtained from the MBVD circuit. Coupled with the automated method, which takes about 10 seconds per resonator to perform a complete extraction cycle, a computer controlled probing station is used to acquire data from several hundred resonators on the wafer upon which the FBARS were fabricated. With this speed and probing capability, it is feasible to wafer map the FBARs for uniformity. Contour plots of the measured resonant frequency and coupling constant k/sub t//sup 2/ will be presented to illustrate the capability.

Dynamic Modeling

Abstract: Dynamic modeling refers to the use of computer programs to simulate the behavior of complex, changing systems. Such systems range from weather forecasting to the environmental impact of a pesticide to the economics of fish harvests. Hannon and Ruth have combined the computing power of the modern personal computer and the ease of use of the simulation software Stella, and written an introduction to modeling that will be welcomed by students in disciplines ranging from biology to chemistry to engineering to economics. The "democratization" of modeling is intended to introduce simulation as an integral part of education which will prepare students to incorporate it routinely into their own areas of specialization.

Understanding Security Behaviors in Personal Computer Usage: A Threat Avoidance Perspective*

Abstract: This study aims to understand the IT threat avoidance behaviors of personal computer users. We tested a research model derived from Technology Threat Avoidance Theory (TTAT) using survey data. We find that users’ IT threat avoidance behavior is predicted by avoidance motivation, which, in turn, is determined by perceived threat, safeguard effectiveness, safeguard cost, and self-efficacy. Users develop a threat perception when they believe that the malicious IT is likely to attack them (perceived susceptibility) and the negative consequences will be severe if they are attacked (perceived severity). When threatened, users are more motivated to avoid the threat if they believe that the safeguarding measure is effective (safeguard effectiveness) and inexpensive (safeguard cost) and they have confidence in using it (self-efficacy). In addition, we find that perceived threat and safeguard effectiveness have a negative interaction on avoidance motivation so that a higher level of perceived threat is associated with a weaker relationship between safeguard effectiveness and avoidance motivation or a higher level of safeguard effectiveness is associated with a weaker relationship between perceived threat and avoidance motivation. These findings provide an enriched understanding about personal computer users’ IT threat avoidance behavior.

Method and apparatus for assessing integrity of computer system software

Abstract: A method and device for reliably assessing the integrity of a computer system's software prevents execution of corrupted programs at time of system initialization, enhancing system security. Programs and data comprising the system's trusted software, including all startup processes, are verified before being utilized. Methods to verify the trusted software use a hierarchy of both modification detection codes and public-key digital signature codes. The top-level codes are placed in a protectable non-volatile storage area, and are used by the startup program to verify the integrity of subsequent programs. A trusted initialization program sets a hardware latch to protect the codes in the non-volatile memory from being overwritten by subsequent untrusted programs. The latch is only reset at system restart, when control returns to the bootstrap program. Software reconfiguration is possible with trusted programs that write new top-level codes while the latch is open. The mechanism itself is immune to malicious software attack when the write-protect latch is closed before running untrusted software. Preferred embodiments in an IBM-compatible personal computer uses the reset switch to initiate a trusted path between the user and a program. Damage from certain classes of computer virus and trojan horse attacks is prevented. A system recovery process is described. A related improved method for user authentication uses a read-and -write memory protection latch to prevent access to sensitive authentication data.