The performance of general-purpose colour CRT monitors in PACS environment

General-purpose colour cathode ray tube (CRT) monitors are used commonly for image display in personal computer-based picture archiving and communication system (PACS) and telemedicine systems. At present, however, we have not enough information about their performance or reliability for this task. Therefore, we studied the performance of five general-purpose colour CRTs and the changes in their performance in a year. Resolution was measured visually using original digital images. Maximum and minimum luminances were measured at the centre and periphery of the CRTs. Distortion was measured in the centre and periphery using original digital images. All the monitors met their specifications. The inhomogeneity of luminance exceeded 20% and varied across the CRTs. Darker monitors took more time to reach stable luminance levels. The corner brightness seemed to be a good estimator of both performance and distortion in colour monitors.     

脑电图中央监护系统设计

介绍一个脑电图中央监护的流程以及整个系统的软件设计,该系统由中央监护站和脑电监护仪联网组成.脑电监护仪用于记录、显示脑电图和病人状态信息,中央监护站通过多用户USB接口与医院内床边脑电监护仪联网.该系统实现了脑电图的长程监护、多床位集中监护,对于阵发性异常脑电图的"捕获"带来很大的方便,拓展了传统脑电图的应用范围,可大大提高医生的工作效率,有利于临床诊治水平的提高.     

脑电图远程集中监护系统的研制

介绍脑电图远程集中监护系统的研制，该系统由中央监护站和脑电监护仪联网组成，脑电监护仪用于记录，显示脑电图和病人状态信息，中央监护站通过RS－485总线与医院内床边脑电监护仪联网，通过公用电话线与远程脑电监护仪通讯。该系统实现了脑电图的长程监护，多床位集中监护和程遥测监护，对于阵发性异常脑电图的“捕获”带来极大方便，拓展了传统脑电图的应用范围，可大大提高医生的工作效率，有利于临床诊治水平的提高。     

On optimal monitor placement for localizing node failures via network tomography

We investigate the problem of placing monitors to localize node failures in a communication network from binary states (normal/failed) of end-to-end paths, under the assumption that a path is in normal state if and only if it contains no failed nodes. To uniquely localize failed nodes, the measurement paths must show different symptoms (path states) under different failure events. Our goal is to deploy the minimum set of monitors to satisfy this condition for a given probing mechanism. We consider three families of probing mechanisms, according to whether measurement paths are (i) arbitrarily controllable, (ii) controllable but cycle-free, or (iii) uncontrollable (i.e., determined by the default routing protocol). We first establish theoretical conditions that characterize network-wide failure identifiability through a per-node identifiability measure that can be efficiently evaluated for the above three probing mechanisms. Leveraging these results, we develop a generic monitor placement algorithm, applicable under any probing mechanism, that incrementally selects monitors to optimize the per-node measure. The proposed algorithm is shown to be optimal for probing mechanism (i), and provides upper and lower bounds on the minimum number of monitors required by the other probing mechanisms. In the special case of single-node failures, we develop an improved monitor placement algorithm that is optimal for probing mechanism (ii) and has linear time complexity. Using these algorithms, we study the impact of the probing mechanism on the number of monitors required for uniquely localizing node failures. Our results based on real network topologies show that although more complicated to implement, probing mechanisms that allow monitors to control measurement paths substantially reduce the required number of monitors.     

Monitoring cache behavior on parallel SMP architectures and related programming tools

This paper describes the ideas and developments of the project EP-CACHE. Within this project new methods and tools are developed to improve the analysis and the optimization of programs for cache architectures, especially for SMP clusters. The tool set comprises the semi-automatic instrumentation of user programs, the monitoring of the cache behavior, the visualization of the measured data, and optimization techniques for improving the user program for better cache usage.

As current hardware performance counters do not give sufficient user relevant information, new hardware monitors are designed that provide more detailed information about the cache utilization related to the data structures and code blocks in the user program. The expense of the hardware and software realization will be assessed to minimize the risk of a real implementation of the investigated monitors. The usefulness of the hardware monitors is evaluated by a cache simulator.     

Motion artifact elimination technology for liquid‐crystal‐display monitors: Advanced dynamic capacitance compensation method

Abstract— A new technology, advanced dynamic capacitance compensation (A‐DCC), for improved dynamic performance of LCD monitors, is presented. Conventional LCD monitors suffer from certain specific artifacts, such as wire‐frame flicker and line dimming, which are not issues for the simpler motion images found in television content. A‐DCC addresses these more‐challenging monitor cases by means of an advanced architecture which analyzes multi‐frame data and applies more comprehensive lookup‐table corrections according to the specific frame sequence.     

覆盖率驱动的芯片功能验证设计与实现

随着芯片集成度的发展,芯片性能越来越高,而上市时间越来越短,芯片验证在芯片设计中非常关键并贯穿于整个设计过程,验证的效率和质量直接决定着芯片的成败。提出了基于覆盖率驱动的芯片功能验证方法,定义了基于功能点覆盖率驱动的验证流程,利用PSL语言描述断言检查很有效,通过模拟工具检查断言是否成功,从而判断设计是否满足系统的功能要求。在网络接口芯片实际应用中,有效地降低了验证工作的复杂度,同时提高了验证的速度和质量。利用功能覆盖率数据判断测试激励的正确性和完整性,同时用覆盖率数据定量评价验证进程,提高了整个设计的效率。     

Structure of weakly 2-dependent siphons

Deadlocks arising from insufficiently marked siphons in flexible manufacturing systems can be controlled by adding monitors to each siphon – too many for large systems. Li and Zhou add monitors to elementary siphons only while controlling the rest of (called dependent) siphons by adjusting control depth variables of elementary siphons. Only a linear number of monitors are required. The control of weakly dependent siphons (WDSs) is rather conservative since only positive terms were considered. The structure for strongly dependent siphons (SDSs) has been studied earlier. Based on this structure, the optimal sequence of adding monitors has been discovered earlier. Better controllability has been discovered to achieve faster and more permissive control. The results have been extended earlier to S³PGR² (systems of simple sequential processes with general resource requirements). This paper explores the structures for WDSs, which, as found in this paper, involve elementary resource circuits interconnecting at more than (for SDSs, exactly) one resource place. This saves the time to compute compound siphons, their complementary sets and T-characteristic vectors. Also it allows us (1) to improve the controllability of WDSs and control siphons and (2) to avoid the time to find independent vectors for elementary siphons. We propose a sufficient and necessary test for adjusting control depth variables in S³PR (systems of simple sequential processes with resources) to avoid the sufficient-only time-consuming linear integer programming test (LIP) (Nondeterministic Polynomial (NP) time complete problem) required previously for some cases.     

Trochilidae:面向众核平台的高性能轻量级虚拟机监控器

虚拟化技术在云计算中广泛应用。传统虚拟化技术对操作系统的一些操作都进行了捕捉与封装,使其越来越复杂,同时也影响了操作系统的性能。针对众核平台的发展趋势和特点,面向众核平台设计并实现了一个轻量级的高性能虚拟机监控器——蜂鸟(Trochilidae)。多操作系统可以同时运行在此虚拟机监控器之上,同时对操作系统性能无损失。在提供传统虚拟机监控器功能的基础上,蜂鸟的代码量仅4000行左右(包括汇编与C代码),降低了系统的复杂度,便于系统的维护与调试。     

Extending the enforcement power of truncation monitors using static analysis

Runtime monitors are a widely used approach to enforcing security policies. Truncation monitors are based on the idea of truncating an execution before a violation occurs. Thus, the range of security policies they can enforce is limited to safety properties. The use of an a priori static analysis of the target program is a possible way of extending the range of monitorable properties. This paper presents an approach to producing an in-lined truncation monitor, which draws upon the above intuition. Based on an a priori knowledge of the program behavior, this approach allows, in some cases, to enforce more than safety properties and is more powerful than a classical truncation mechanism. We provide and prove a theorem stating that a truncation enforcement mechanism considering only the set of possible executions of a specific program is strictly more powerful than a mechanism considering all the executions over an alphabet of actions.     

Controllability of control and mixture weakly dependent siphons in S3PR

Deadlocks in a flexible manufacturing system modelled by Petri nets arise from insufficiently marked siphons. Monitors are added to control these siphons to avoid deadlocks rendering the system too complicated since the total number of monitors grows exponentially. Li and Zhou propose to add monitors only to elementary siphons while controlling the other (strongly or weakly) dependent siphons by adjusting control depth variables. To avoid generating new siphons, the control arcs are ended at source transitions of process nets. This disturbs the original model more and hence loses more live states. Negative terms in the controllability make the control policy for weakly dependent siphons rather conservative. We studied earlier on the controllability of strongly dependent siphons and proposed to add monitors in the order of basic, compound, control, partial mixture and full mixture (strongly dependent) siphons to reduce the number of mixed integer programming iterations and redundant monitors. This article further investigates the controllability of siphons derived from weakly 2-compound siphons. We discover that the controllability for weakly and strongly compound siphons is similar. It no longer holds for control and mixture siphons. Some control and mixture siphons, derived from strongly 2-compound siphons are not redundant – no longer so for those derived from weakly 2-compound siphons; that is all control and mixture siphons are redundant. They do not need to be the conservative one as proposed by Li and Zhou. Thus, we can adopt the maximally permissive control policy even though new siphons are generated.     

On systematic methods to remove redundant monitors from liveness-enforcing net supervisors

Petri nets based deadlock prevention for flexible manufacturing systems has received much attention over the past decade, primarily due to the seminal work of Ezpeleta et al. in 1995. A Petri net based deadlock prevention mechanism is usually implemented by adding monitors or control places to a plant Petri net model such that liveness can be enforced. The significance of this methodology lies in that both a plant model and its supervisor are in a same formalism-Petri nets. Due to the inherent complexity of Petri nets, in theory, the number of additional monitors that have to been added to achieve liveness-enforcement purpose for an uncontrolled plant model is exponential with respect to the size of the model. This paper first proposes a systematic method to minimize the number of additional monitors in a liveness-enforcing Petri net supervisor such that the resultant net system has the same permissive behavior while liveness can still be preserved. Furthermore, for the liveness-enforcing Petri net supervisors of flexible manufacturing systems, which have some particular property, an algorithm is developed such that more permissive liveness-enforcing Petri net supervisors can be obtained after liveness-restrictive monitor removal. Compared with the existing techniques of eliminating redundant monitors in the literature, the complete state enumeration of a supervisor is avoided, which implies the high computational efficiency of the methods in this paper. Flexible manufacturing examples are used to demonstrate the proposed approaches.     

Pulsar: an extensible tool for monitoring large Unix sites

Many problems can crop up unexpectedly on Unix computers, and the administrator must be able to detect and react to these problems quickly. If a site has more than a few computers, the effort needed to keep abreast of problems can lead to unresponsive administration. Pulse monitors form a simple but effective tool to assist the administrator in this task. This paper describes the Pulsar pulse-monitor package. It is composed of a presenter, which provides a graphical user interface to the administrator, a set of individual pulse monitors, which examine aspects of the status on a host and communicate their results to the presenter, and a scheduler, which executes pulse monitors according to the frequency specified by its configuration files. The set of pulse monitors is easily extended by the administrator to provide warnings about any situation that can be algorithmically detected. © 1997 John Wiley & Sons, Ltd.     

Cervical spine biomechanics and task performance during touchscreen computer operations

The effects of different touchscreen interface designs on operators' task performance and cervical spine biomechanics were investigated in the current study. Fifteen male participants performed “Whac-a-Mole” type of visual target pinpointing tasks on a touchscreen monitor with different display sizes, icon sizes, icon colors and task difficulties. Participants' task performance, cervical spine biomechanics and upper extremity muscle activities were recorded and compared. Results demonstrated that an oversized desktop touchscreen monitor and small icons generated negative impacts on participants’ task performance and biomechanical measurements. Lighter icon color and more difficult task requirement generated worse task performance but had limited impact on cervical spine biomechanics. In addition, when using an oversized touchscreen monitor, the impacts of icon size and task difficulty seem to be magnified. Our results demonstrated that a more human-oriented interface design could help improve task performance and reduce neck and upper extremity injuries while operating touchscreen monitors.Relevance to industryIn this study we investigated how a number of different design factors could influence task performance as well as cervical spine biomechanics when using touchscreen monitors. Knowledge gained from the current study could help the design of future applications that involve finger touching operations on touchscreen monitors.     

Autonomic load balancing of flow monitors

In monitoring flows at routers for flow analysis or deep packet inspection, the monitor calculates hash values from the flow ID of each packet arriving at the input port of the router. Therefore, the monitors must update the flow table at the transmission line rate, so high-speed and high-cost memory, such as SRAM, is used for the flow table. This requires the monitors to limit the monitoring target to just some of the flows. However, if the monitors randomly select the monitoring targets, multiple routers on the route will sometimes monitor the same flow, or no monitors will monitor a flow. To maximize the number of monitored flows in the entire network, the monitors must select the monitoring targets while maintaining a balanced load among them. We propose an autonomous load-balancing method where monitors exchange information on monitor load only with adjacent monitors. Numerical evaluations using the actual traffic matrix of Internet2 show that the proposed method improves the total monitored flow count by about 50% compared with that of independent sampling. Moreover, we evaluate the load-balancing effect on 36 backbone networks of commercial ISPs.     

Interfacing a serial bus microcomputer to a distributed network

Special nuclear material in long-term storage in a vault is an attractive target for a diverter. A serial bus data acquisition network has been implemented utilizing single-component microcomputers. The distributed network enables constant surveillance of this material utilizing a variety of sensors. The serial bus protocol includes broadcast commands, network control, microcomputer diagnostics and data collection.A single-component microcomputer collects data from a Geiger-Müller tube that monitors γ emissions and from a scale that monitors the total weight of the container and contents. A network of the microcomputer shelf monitors reports the acquired data to a minicomputer for analysis, alarm if necessary and storage. One network consisting of approximately 100 monitors has been collecting data for over 1 year. The objective of this research program has been to develop a reliable inexpensive monitor network and associated data-processing equipment capable of real-time monitoring.     

基于嗅探技术的内部网络安全研究

网络边界处的防火墙系统可以有效防御一些来自外网的攻击,在入侵检测系统的实时保护下,理论上可以保障内网安全无忧。然而,内部网络的非法操作更隐蔽、更有威胁。针对这种情况,通过嗅探技术对内网进行实时的流量监控和数据包分析,较好地加强和保障了内网的安全。     

A universal data acquisition program for use with anesthetic monitors and Windows 3.0.

A method is described whereby a single program can acquire data from any patient monitor which has a data output facility. No changes are necessary to the program for different monitors. It provides a method of standardizing data transfer between computers and monitors. The program runs in the Microsoft Windows 3.0 operating system. It utilizes Dynamic Link Libraries (DLL) which enable the operating system to communicate with monitors. Each kind of monitor will use a unique DLL in order to provide a standard interface to the Windows 3.0 operating system.     

Which security policies are enforceable by runtime monitors? A survey

Runtime monitoring is a widely used approach to ensure code safety. Several implementations of formal monitors have been proposed in the literature, and these differ with respect to the set of security policies that they are capable of enforcing. In this survey, we examine the evolution of knowledge regarding the issue of precisely which security policies monitors are capable of enforcing. We identify three stages in this evolution. In the first stage, we discuss initial limits on the set of enforceable properties and various ways in which this set can be extended. The second stage presents studies that identify constraints to the enforcement power of monitors. In the third stage, we present a final series of studies that suggest various alternative definitions of enforcement, which specify both the set of properties the monitors can enforce as well as the manner by which this enforcement is provided.