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.

An iterative knowledge-based scoring function for protein–protein recognition

Abstract: Using an efficient iterative method, we have developed a distance-dependent knowledge-based scoring function to predict protein-protein interactions. The function, referred to as ITScore-PP, was derived using the crystal structures of a training set of 851 protein-protein dimeric complexes containing true biological interfaces. The key idea of the iterative method for deriving ITScore-PP is to improve the interatomic pair potentials by iteration, until the pair potentials can distinguish true binding modes from decoy modes for the protein-protein complexes in the training set. The iterative method circumvents the challenging reference state problem in deriving knowledge-based potentials. The derived scoring function was used to evaluate the ligand orientations generated by ZDOCK 2.1 and the native ligand structures on a diverse set of 91 protein-protein complexes. For the bound test cases, ITScore-PP yielded a success rate of 98.9% if the top 10 ranked orientations were considered. For the more realistic unbound test cases, the corresponding success rate was 40.7%. Furthermore, for faster orientational sampling purpose, several residue-level knowledge-based scoring functions were also derived following the similar iterative procedure. Among them, the scoring function that uses the side-chain center of mass (SCM) to represent a residue, referred to as ITScore-PP(SCM), showed the best performance and yielded success rates of 71.4% and 30.8% for the bound and unbound cases, respectively, when the top 10 orientations were considered. ITScore-PP was further tested using two other published protein-protein docking decoy sets, the ZDOCK decoy set and the RosettaDock decoy set. In addition to binding mode prediction, the binding scores predicted by ITScore-PP also correlated well with the experimentally determined binding affinities, yielding a correlation coefficient of R = 0.71 on a test set of 74 protein-protein complexes with known affinities. ITScore-PP is computationally efficient. The average run time for ITScore-PP was about 0.03 second per orientation (including optimization) on a personal computer with 3.2 GHz Pentium IV CPU and 3.0 GB RAM. The computational speed of ITScore-PP(SCM) is about an order of magnitude faster than that of ITScore-PP. ITScore-PP and/or ITScore-PP(SCM) can be combined with efficient protein docking software to study protein-protein recognition.

Quick Computation of Spatial Autoregressive Estimators

Abstract: Spatial estimators usually require the manipulation of n2 relations among n observations and use operations such as determinants, eigenvalues, and inverses whose operation counts grow at a rate proportional to n3. This paper provides ways to quickly compute estimates when the dependent variable follows a spatial autoregressive process, which by appropriate specification of the independent variables can subsume the case when the errors follow a spatial autoregressive process. Since only nearby observations tend to affect a given observation, most observations have no effect and hence the spatial weight matrix becomes sparse. By exploiting sparsity and rearranging computations, one can compute estimates at low cost. As a demonstration of the efficacy of these techniques, the paper provides a Monte Carlo study whereby 3,107 observation regressions require only 0.1 seconds each when using Matlab on a 200 Mhz Pentium Pro personal computer. In addition, the paper illustrates these techniques by examining voting behavior across U.S. counties in the 1980 presidential election.

Usage patterns and sources of assistance for personal computer users

Abstract: This study investigates the usage pattern and sources of assistance for personal computer(PC) users in twelve organizations. The study found that PCs attract new computer users and the extent of PC usage was correlated with prior computer knowledge. The most important reason for using PCs was for specific professional work. Although managers spend fewer hours than their staff using their PCs, there was no relationship between the diversity of applications and organizational position. Overall, users were satisfied with their PCs, but not with the information they obtained from the written sources (i.e., manuals, documents, and journals). The best source of information for PC users were their own colleagues and their organization's information systems staff. Moreover, "lead users" played an important role as consultants to other users.Two divisions of a large manufacturing firm in our sample introduced PCs concurrently but under different policies. The two units provided a natural setting for assessing the impact of the technology. In the division that underwent extensive planning prior to the introduction of this technology, we found that users made significantly more use of internal consulting. In contrast, in the other division, where management had adopted an "individual initiatives and maximum freedom" policy for introducing this technology, the users made significantly less use of internal consulting, approaching outside vendors instead even though they felt the information obtained from the vendors was significantly lower in quality. Implications fort he management of personal computer technology are discussed.

Method and apparatus for facilitating physiological coherence and autonomic balance

Abstract: The invention is a method, and apparatus for determining the state of entrainment between biological systems which exhibit oscillatory behavior such as heart rhythms, respiration, blood pressure waves, low frequency brain waves, based on a determination of heart rate variability (HRV), and an evaluation of the power spectrum thereof. Entrainment reflects a harmonious balance between the two branches of the autonomous nervous system within the body. This internal state of heightened physiological efficiency enhances health, and promotes optimal performance. According to one embodiment, a method is used to determine the entrainment level based on an entrainment parameter related to HRV. The method first determines the power distribution spectrum (PSD), and then calculates an entrainment parameter (EP), which is a measure of the power distribution in the HRV spectrum. In one embodiment, an apparatus (12) is provided for monitoring the heart beat, and presenting this information via a personal computer (14), handheld device, or other processing means.

Voip enabled femtocell with a usb transceiver station

Abstract: Telephone calls between a mobile station (MS) and the mobile network or PSTN are routed through the Internet via VoIP using a femtocell, as opposed to the traditional macrocellular network. The femtocell can comprise a USB Transceiver Station that is connected to a personal computer through a universal serial bus port, which provides both power and a multi-megabit per second connection between the personal computer and the USB transceiver station. The USB transceiver station can comprise a microcontroller to manage signaling between the RF front end/baseband processor and the personal computer, as well as a precise timing mechanism to assist the synchronization of femtocell timing with the surrounding macrocellular network, if it is present. The USB transceiver station can have a compact form factor that that facilitates a high degree of portability by the subscriber, such as being readily attachable to their keychain.