Automated immunomagnetic processing and separation of Legionella pneumophila with manual detection by sandwich ELISA and PCR amplification of the ompS gene

The culture-independent and automated detection of bacteria in the environment is a scientific and technological challenge. For detection alone, a number of sensitive methods are known (e.g., PCR, enzyme-linked immunosorbent assay [ELISA], fluorescent in situ hybridization) but a major problem remaining is the enrichment and separation of the bacteria that usually occur at low concentrations. Here, we present an automated capturing and separation system, which can easily be combined with one of the sensitive detection techniques. We have developed a method for enrichment and detection of Legionella pneumophila in liquid media. Concentrated microorganisms were either detected by PCR or by sandwich ELISA. The limit of detection with the immunological assay was about 750 bacteria. Using PCR, the equivalent of about 2000 genomes could be detected. The assays were then transferred to a laboratory prototype for automated processing. It was possible to automatically enrich L. pneumophila by immunomagnetic separation (IMS), and again, the bacteria were detected by sandwich ELISA and PCR amplification of the ompS gene. As a novel aspect, ompS gene was used for the first time as a target for the detection of L. pneumophila on magnetic beads. The aim of this work was to develop an automated procedure and a device for IMS of bacteria. With Legionella as a model organism, we could show that such a novel fully automated system can be an alternative to time-consuming conventional cultivation methods for detecting bacteria or other microorganisms.     

A theory of translation from relational queries to hierarchicalqueries

In a heterogeneous database system, a query for one type of database system (i.e., a source query) may have to be translated to an equivalent query (or queries) for execution in a different type of database system (i.e., a target query). Usually, for a given source query, there is more than one possible target query translation. Some of them can be executed more efficiently than others by the receiving database system. Developing a translation procedure for each type of database system is time-consuming and expensive. We abstract a generic hierarchical database system (GHDBS) which has properties common to database systems whose schema contains hierarchical structures (e.g., System 2000, IMS, and some object-oriented database systems). We develop principles of query translation with GHDBS as the receiving database system. Translation into any specific system can be accomplished by a translation into the general system with refinements to reflect the characteristics of the specific system. We develop rules that guarantee correctness of the target queries, where correctness means that the target query is equivalent to the source query. We also provide rules that can guarantee a minimum number of target queries in cases when one source query needs to be translated to multiple target queries. Since the minimum number of target queries implies the minimum number of times the underlying system is invoked, efficiency is taken into consideration     

Calculus interdependency,personality contingency,and causal asymmetry: Toward a configurational privacy calculus model of information disclosure

This study proposes a configurational privacy calculus model (CPCM) to understand calculus interdependency, personality contingency, and causal asymmetry in the information disclosure behavior in social networking sites (SNS). The results based on qualitative comparative analysis (QCA) showed that high disclosure can be caused by the configurations with the presence of at least one perceived benefit among the three types of benefits (i.e., self-expression, life documentation, and social rewards) while the absence of privacy risks, or the configurations with the presence of both perceived benefits and privacy risks meanwhile with the presence of behavioral activation system (BAS) but the absence of behavioral inhibition system (BIS). In contrast, low disclosure can be caused by the configurations with the absence of all the three types of perceived benefits, or the configurations with the presence of both perceived benefits and privacy risks meanwhile with the presence of BIS, but the absence of BAS.     

Task-Structures,Knowledge Acquisition and Learning

One of the old saws about learning in AI is that an agent can only learn what it can be told, i.e., the agent has to have a vocabulary for the target structure which is to be acquired by learning. What this vocabulary is, for various tasks, is an issue that is common to whether one is building a knowledge system by learning or by other more direct forms of knowledge acquisition. I long have argued that both the forms of declarative knowledge required for problem solving as well as problem-solving strategies are functions of the problem-solving task and have identified a family of generic tasks that can be used as building blocks for the construction of knowledge systems. In this editorial, I discuss the implication of this line of research for knowledge acquisition and learning.     

Infinitesimal perturbation analysis of a single-stage fluid queue with loss feedback and non-responsive competing traffic

In this paper we perform Infinitesimal Perturbation Analysis (IPA) for a single-stage stochastic fluid queue that is shared between two competing sources, one that employs additive loss-feedback congestion control and the other that employs no congestion-control (i.e., it is unresponsive). This scenario is applicable within the realm of computer communication networks particularly at bottleneck router queues where multiple and diverse flows compete for bandwidth. We optimize the tradeoff between total loss volume and queue workload (a measure for queueing delay). Although a sound knowledge of the system’s dynamics is required to derive the IPA gradient estimators, no knowledge of the underlying probability distributions governing the system is required. What results are fairly simple counting processes, whose values can be computed directly from an ongoing live stream of traffic.     

SAGE: an automatic analyzing system for a new high-performance SoC architecture––processor-in-memory

Continuous improvements in semiconductor fabrication density are supporting new classes of System-on-a-Chip (SoC) architectures that combine extensive processing logic/processor with high-density memory. Such architectures are generally called Processor-in-Memory (PIM) or Intelligent Memory (I-RAM) and can support high-performance computing by reducing the performance gap between the processor and the memory. The PIM architecture combines various processors in a single system. These processors are characterized by their computation and memory-access capabilities. Therefore, a novel strategy must be developed to identify their capabilities and dispatch the most appropriate jobs to them in order to exploit them fully. Accordingly, this study presents an automatic source-to-source parallelizing system, called statement-analysis-grouping-evaluation (SAGE), to exploit the advantages of PIM architectures. Unlike conventional iteration-based parallelizing systems, SAGE adopts statement-based analyzing approaches. This study addresses the configuration of a PIM architecture with one host processor (i.e., the main processor in state-of-the-art computer systems) and one memory processor (i.e., the computing logic integrated with the memory). The strategy of the SAGE system, in which the original program is decomposed into blocks and a feasible execution schedule is produced for the host and memory processors, is investigated as well. The experimental results for real benchmarks are also discussed.     

Mechanizing Weakly Ground Termination Proving of Term Rewriting Systems by Structural and Cover-Set Inductions

The paper presents three formal proving methods for generalized weakly ground terminating property, i.e., weakly terminating property in a restricted domain of a term rewriting system, one with structural induction, one with cover-set induction, and the third without induction, and describes their mechanization based on a meta-computation model for term rewriting systems-dynamic term rewriting calculus. The methods can be applied to non-terminating, non-confluent and/or non-left-linear term rewriting systems. They can do "forward proving" by applying propositions in the proof, as well as "backward proving" by discovering lemmas during the proof.     

Correcting the Market Failure in Work Trips with Work Rescheduling: An Analysis Using Bi-level Models for the Firm-workers Interplay

Compulsory trips (e.g., work trips) contribute with the major part of the congestion in the morning peak. It also prevents the society to reach a social optimum (the solution that maximizes welfare) because the presence of the private utility of one the agents (the firm), acting as a dominant agent, does not account for the additional costs imposed in their workers (congestion) as well as the costs imposed to the rest of the society (i.e., congestion, pollution). In this paper, a study of a strategy to influence the demand generator by relaxing the arrival constraints is presented. Bi-level programming models are used to investigate the equilibrium reached from the firm-workers interplay which helps to explain how the market failure arises. The evaluation includes the use of incentives to induce the shift to less congested periods and the case of the social system optimum in which a planner objective is incorporated as a third agent usually seeking to improve social welfare (improve productivity of the firm while at the same time reduce the total system travel time). The later is used to show that it is possible to provide a more efficient solution which better off society. A numerical example is used to (1) show the nature of the market failure, (2) evaluate the social system optimum, and (3) show how a congestion tax or an optimal incentive can help to correct the market failure. The results also corroborate that these mechanisms are more likely to be more efficient when firms face little production effects on time and workers do not high opportunity costs for starting at off peak periods.     

构建新型高性能与高可用的键值数据库系统

近年来,写密集型应用程序越来越普遍.如何有效地处理这种工作负载,是数据库系统领域深入研究的方向之一.写操作开销主要由以下两个方面的因素构成：（1）硬件级别,即写操作引起的I/O,目前无法在短时间内消除这种开销;（2）软件开销,即修改内存数据拷贝以及构造日志记录造成的多次写操作.日志即数据（log-as-database,称其为单拷贝系统）的架构能够减少写操作引起的I/O,同时降低软件方面的开销.目前,业界对单拷贝系统展现出浓厚的兴趣.现有的单拷贝系统大部分建立在特殊的基础设施之上,例如infiniband或NVRam（非易失性随机存取存储器）,这种基础设施尚未达到广泛可用或者是依托他系统（例如Dynamo）构建,这种方法缺乏灵活性与普适性.在商用机器环境中,自底向上构建了一个称为LogStore的键值数据库系统,采用log-as-database设计理念,以充分利用单拷贝系统的优点,在提升写操作性能的同时,有效缩短主备数据之间的差距.在系统中内嵌复制协议达到高可用性而不是依赖其他系统,使得系统灵活可控.系统新颖的查询执行模型将执行线程与特定分片绑定,结合多版本并发控制技术,以无锁的方式消除读写冲突、写写冲突以及上下文切换开销.用YCSB对系统性能进行了详细的评估,对比主流的键值系统HBase以及单拷贝系统实现LogBase,LogStore在写密集型工作负载上性能要优4倍左右.在崩溃恢复方面,LogStore可在1分钟之内完成TB级别数据规模的恢复,比LogBase要快1个数量级以上.     

用于图像分割的自适应距离保持水平集演化

Li等人提出的距离保持水平集方法有传统变分水平集方法不具备的许多优点,然而,它有初始曲线必须包围目标物体或完全置于目标物体内部或外部的缺点.提出一种自适应距离保持水平集方法,它无须初始曲线包围目标物体或完全置于目标物体内部或外部,即初始曲线可以置于图像的任何地方.它能够解决原方法所不能解决的一些图像分割问题,例如,能够从任意选取的一条初始曲线出发自动检测目标物体的内外轮廓,检测多目标物体以及深度凹陷区域的边缘,并能较好地提取目标物体的弱边界.对几幅具有不同目标边界形态的合成图像和自然图像进行了实验,结果都取得了预期的分割效果.     

Trace- and failure-based semantics for responsiveness

We study open systems modeled as Petri nets with an interface for asynchronous (i.e., buffered) communication with other open systems. As a minimal requirement for successful communication, we investigate responsiveness, which guarantees that an open system and its environment always have the possibility to communicate. We investigate responsiveness with and without final states and also their respective bounded variants, where the number of pending messages never exceeds a previously known bound. Responsiveness accordance describes when one open system can be safely replaced by another open system. We present a trace-based characterization for each accordance variant. As none of the relations turns out to be compositional (i.e., it is no precongruence), we characterize the coarsest compositional relation (i.e., the coarsest precongruence) that is contained in each relation, using a variation of should testing. For the two unbounded variants, the precongruences are not decidable, but for the two bounded variants we show decidability.     

FUZZY LOGIC OPERATORS IN DECISION-MAKING

The fuzzy logic operators are used to decide the following multicriteria decision-making problem. A finite set of alternatives is evaluated by a set of fuzzy criteria, i.e., fuzzy relations, which may be either fuzzy preference, or similarity, or likeness relations. The problem is to construct an evaluation procedure to compare the set of alternatives according to the whole set of criteria, i.e., to aggregate the private fuzzy relations in order to get the union relation as a fuzzy one, enhancing to solve the ranking, choice, or cluster problem. Some properties of these operators, required to decide the ranking, choice, or cluster problems and depending on the properties of the private relations, are proved. A numerical example is given as well.     

On a unified architecture for video-on-demand services

Current video-on-demand (VoD)) systems can be classified into two categories: 1) true-Voll) (TVoD) and 2) near-VoD (NVod)). TVoD systems allocate a dedicated channel for every user to achieve short response times so that the user can select what video to play, when to play it, and perform interactive VCR-like controls at will. By contrast, NVoD systems transmit videos repeatedly over multiple broadcast or multicast channels to enable multiple users to share a single video channel so that system cost can be substantially reduced. The tradeoffs are limited video selections, fixed playback schedule, and limited or no interactive control. TVoD systems can be considered as one extreme where service quality is maximized, while NVoD systems can be considered as the other extreme where system cost is minimized. This paper proposes a novel architecture called Unified VoD) (UVoD) that can be configured to achieve cost-performance tradeoff anywhere between the two extremes (i.e., TVoD and NVoD). Assuming that a video client can concurrently receive two video channels and has local buffers for caching a portion of the video data, the proposed UVoD architecture can achieve significant performance gains (e.g., 400% more capacity for a 500-channel system) over TVoD under the same latency constraint. This paper presents the UVoD architecture, establishes a performance model, and analyzes UVoD's performance via numerical and simulation results     

Inheritance of workflows: an approach to tackling problems related to change

Inheritance is one of the key issues of object-orientation. The inheritance mechanism allows for the definition of a subclass which inherits the features of a specific superclass. When adapting a workflow process definition to specific needs (ad-hoc change) or changing the structure of the workflow process as a result of reengineering efforts (evolutionary change), inheritance concepts are useful to check whether the new workflow process inherits some desirable properties of the old workflow process. Today's workflow management systems have problems dealing with both ad-hoc changes and evolutionary changes. As a result, a workflow management system is not used to support dynamically changing workflow processes or the workflow processes are supported in a rigid manner, i.e., changes are not allowed or handled outside of the workflow management system. In this paper, we propose inheritance-preserving transformation rules for workflow processes and show that these rules can be used to avoid problems such as the “dynamic-change bug.” The dynamic-change bug refers to errors introduced by migrating a case (i.e., a process instance) from an old process definition to a new one. A transfer from an old process to a new process can lead to duplication of work, skipping of tasks, deadlocks, and livelocks. Restricting change to the inheritance-preserving transformation rules guarantees transfers without any of these problems. Moreover, the transformation rules can also be used to extract aggregate management information in case more than one version of a workflow process cannot be avoided.     

Semidefinite programming duality and linear time-invariant systems

Several important problems in control theory can be reformulated as semidefinite programming problems, i.e., minimization of a linear objective subject to linear matrix inequality (LMI) constraints. From convex optimization duality theory, conditions for infeasibility of the LMIs, as well as dual optimization problems, can be formulated. These can in turn be reinterpreted in control or system theoretic terms, often yielding new results or new proofs for existing results from control theory. We explore such connections for a few problems associated with linear time-invariant systems.     

The structure of robust observers

In this short paper conventional observers for linear time-invariant systems are shown to be structurally inadequate from a sensitivity standpoint. It is proved that if a linear dynamic system is to provide observer action despite arbitrary small perturbations in a specified subset of its parameters, it must 1) be a closed-loop system, i.e., be driven by the observer error, 2) possess redundancy, i.e., the observer must be generating, implicitly or explicitly, at least one linear combination of states that is already contained in the measurements, and 3) contain a perturbation-free model of the portion of the system observable from the external input to the observer. The procedure for design of "robust" observers possessing the above structural features is established and discussed.     

ACME: A scalable parallel system for extracting frequent patterns from a very long sequence

Modern applications, including bioinformatics, time series, and web log analysis, require the extraction of frequent patterns, called motifs, from one very long (i.e., several gigabytes) sequence. Existing approaches are either heuristics that are error-prone, or exact (also called combinatorial) methods that are extremely slow, therefore, applicable only to very small sequences (i.e., in the order of megabytes). This paper presents ACME, a combinatorial approach that scales to gigabyte-long sequences and is the first to support supermaximal motifs. ACME is a versatile parallel system that can be deployed on desktop multi-core systems, or on thousands of CPUs in the cloud. However, merely using more compute nodes does not guarantee efficiency, because of the related overheads. To this end, ACME introduces an automatic tuning mechanism that suggests the appropriate number of CPUs to utilize, in order to meet the user constraints in terms of run time, while minimizing the financial cost of cloud resources. Our experiments show that, compared to the state of the art, ACME supports three orders of magnitude longer sequences (e.g., DNA for the entire human genome); handles large alphabets (e.g., English alphabet for Wikipedia); scales out to 16,384 CPUs on a supercomputer; and supports elastic deployment in the cloud.     

Target cuing in visual search: the effects of conformality and display location on the allocation of visual attention

Two experiments were performed to examine how frame of reference (world-referenced vs. screen-referenced) and target expectancy can modulate the effects of target cuing in directing attention for see-through helmet-mounted displays (HMDs). In the first experiment, the degree of world referencing was varied by the spatial accuracy of the cue; in the second, the degree of world referencing was varied more radically between a world-referenced HMD and a hand-held display. Participants were asked to detect, identify, and give azimuth information for targets hidden in terrain presented in the far domain (i.e., the world) while performing a monitoring task in the near domain (i.e., the display). The results of both experiments revealed a cost-benefit trade-off for cuing such that the presence of cuing aided the target detection task for expected targets but drew attention away from the presence of unexpected targets in the environment. Analyses support the observation that this effect can be mediated by the display: The world-referenced display reduced the cost of cognitive tunneling relative to the screen-referenced display in Experiment 1; this cost was further reduced in Experiment 2 when participants were using a hand-held display. Potential applications of this research include important design guidelines and specifications for automated target recognition systems as well as any terrain-and-targeting display system in which superimposed symbology is included, specifically in assessing the costs and benefits of attentional cuing and the means by which this information is displayed.