Concurrent Protocol Research Articles

The Impact of Data Quality Tags on Decision-Making Outcomes and Process

It has been proposed that metadata describing data quality (DQ), termed DQ tags, be made available in situations where decision makers are unfamiliar with the data context, for example, in data warehouses. However, there have been conflicting reports as to the impact of such DQ tags on decision-making outcomes. Early studies did not explicitly consider the usability and semantics of the DQ tag designs used experimentally or the impact of such tags on decision process, except in suggestions for future research. This study addresses these issues, focusing on the design of usable DQ tags whose semantics are explicitly specified and exploring the impact of such DQ tags on decision outcomes and process. We use the information quality framework InfoQual, the interaction design technique of contextual inquiry, and cognitive process tracing to address DQ tag semantics, usability, and impact on decision process, respectively. In distinct contrast to earlier laboratory experiments, there was no evidence that the preferred decision choice changed with DQ tags, but decision time was significantly increased and there were indications of reduced consensus. These results can be explained by understanding the impact of DQ tags on decision process using concurrent protocol analysis, which involves participants verbalizing thoughts while making a decision. The protocol analysis study shows that DQ tags are associated with increased cognitive processing in the earlier phases of decision making, which delays generation of decision alternatives.

RESULTS OF CONCURRENT CHEMORADIATION IN HEAD AND NECK CANCER WITH HYPOFRACTIONATED PROTOCOL OF 60GY/25#/5 WEEKS WITH WEEKLY CISPLATIN

RESULTS OF CONCURRENT CHEMORADIATION IN HEAD AND NECK CANCER WITH HYPOFRACTIONATED PROTOCOL OF 60GY/25#/5 WEEKS WITH WEEKLY CISPLATIN

Concurrent multipath transfer protocol used in ad hoc networks

This study studies the received buffer blocking problem caused by traditional concurrent multipath transfer protocol. The authors propose a new transport protocol, named wireless concurrent multipath transfer stream control transport protocol (WCMT-SCTP), to solve the received buffer blocking problem. It can bind certain data streams to certain paths and use multiple active paths to transfer data simultaneously. The authors evaluate the performance of WCMT-SCTP through theoretical analysis and extensive simulation. Both simulation and analysis results show WCMT-SCTP can improve the system throughput obviously and keep the independence of data streams.

Improving Throughput of Starved TCP Flow by Sidestepping Bottleneck Nodes Using Concurrent Transmission

The TCP congestion control mechanism along with unfairness problem poses poor performance when IEEE 802.11 MAC protocol is used in multi-hop ad hoc networks because the traditional TCP has poor interaction with the IEEE 802.11 MAC protocol. Because of the greedy nature of TCP, starvation problem of TCP flows with longer paths is severe. In this paper, we first illustrate that the fairness, congestion control and medium contention are closely coupled issues and the spatial reuse of the channel can improve the performance of wireless ad hoc network. By using concurrent transmission protocol at the MAC layer, like CTMAC, in multi-hop networks we can achieve simultaneous transmissions within the interference regions. Further, we illustrate with extensive simulations in ns-2 that by scheduling multiple concurrent transmissions along the path links, the starvation problem due to greedy nature of TCP can be eliminated and ensuing higher flow throughput and lower end-to-end delay.

Formal methods applied to high‐performance computing software design: a case study of MPI one‐sided communication‐based locking

AbstractThere is a growing need to address the complexity of verifying the numerous concurrent protocols employed in the high‐performance computing software. Today's approaches for verification consist of testing detailed implementations of these protocols. Unfortunately, this approach can seldom show the absence of bugs, and often results in serious bugs escaping into the deployed software. An approach called Model Checking has been demonstrated to be eminently helpful in debugging these protocols early in the software life cycle by offering the ability to represent and exhaustively analyze simplified formal protocol models. The effectiveness of model checking has yet to be adequately demonstrated in high‐performance computing. This paper presents a case study of a concurrent protocol that was thought to be sufficiently well tested, but proved to contain two very non‐obvious deadlocks in them. These bugs were automatically detected through model checking. The protocol models in which these bugs were detected were also easy to create. Recent work in our group demonstrates that even this tedium of model creation can be eliminated by employing dynamic source‐code‐level analysis methods. Our case study comes from the important domain of Message Passing Interface (MPI)‐based programming, which is universally employed for simulating and predicting anything from the structural integrity of combustion chambers to the path of hurricanes. We argue that model checking must be taught as well as used widely within HPC, given this and similar success stories. Copyright © 2009 John Wiley & Sons, Ltd.

TRANSLATIONAL PERSPECTIVES — TRANSIENT EPIGENETIC GENE THERAPY: HAZARD-FREE CELL REPROGRAMMING APPROACH AND RISING ARM OF A UNIVERSAL STEM CELL GENE THERAPY PLATFORM

Random integration of retroviral transgenes is a major oncogenic hazard that hampers both current clinical gene therapy trials and the genesis of clinical-grade induced pluripotent stem (iPS) cells. Noticeably, we have devised a universal stem cell gene therapy platform aimed at eliminating random integration of therapeutic DNA, at reversing inherited diseases including mitochondrial (mt)DNA ones by reestablishing wild-type genomic homeostasis, and at tackling both inherited and acquired/aging disorders through long-term or transient gene therapy protocols culminating in synergistic combinations. Our platform has a transient epigenetic arm directed at long-term transcriptional inactivation/activation of endogenous genes through the transient action of promoter-specific siRNAs or sense/antisense oligonucleotides, thereby opening an attractive avenue for hazard-free reprogramming of therapeutic iPS cells. Therefore, in addition to its obvious original applications such as long-term transcriptional silencing of autosomal-dominant mutant alleles, the transient epigenetic gene therapy arm could initiate the clinical iPS cell era whereby epigenetic reprogramming of patient somatic cells will not only drive regenerative medicine sensu stricto but also the other arms of our universal stem cell gene therapy platform. Both product and drive of our platform, such hazard-free iPS cells and their derivatives should accommodate all kinds of protocols including 1) long-term gene therapy mediated by endonuclease-boosted gene targeting (gene repair/alteration or targeted transgene integration) or cybridization (mtDNA transfer), and 2) transient regenerative gene therapy aimed at synergizing both regenerative cell therapy sensu stricto and long-term/epigenetic gene therapy through the magnification of the homing/regenerative/differentiative potential of therapeutic stem cells. Our approach is thus discussed 1) in light of emerging concurrent transgene-free reprogramming protocols that rely on protein transduction, small molecules or unintegrating vectors and 2) in terms of somatic cell genetic-like breakthrough in which somatic cells can be safely reprogrammed ex vivo into patient-specific pluripotent stem cells, amplified, engineered through standard/personalized protocols, subjected to potential clonal selections and lineage commitments, and then returned to the patient, thereby driving effective therapeutic repopulative/regenerative dynamics into relevant niches (long-term engraftment) and tissues (basic and regenerative cell turn-over).

Noun, verb, or adjective? L2 learners' sensitivity to cues to word class

This study investigates learners' knowledge of word classes (i.e. noun, verb, adjective) in their second language (L2). Although some L2 studies have examined the problem of word class indirectly through a focus on vocabulary and the teaching of derivational morphology (Morin, 2003, 2006; Schmitt & Zimmerman, 2002), little is known about learners' sensitivity to word class contrasts (e.g. fuerte ‘strong’ versus fuerza ‘strength’). The present study utilised concurrent and retrospective think-aloud protocols to examine learners' attention to different sorts of cues to word class in Spanish. The participants, beginning-level learners of Spanish (n = 35), completed a forced-choice task that targeted word class contrasts in various syntactic contexts. The results indicate that learners attended to grammatical cues frequently, with these accounting for 45% of the total cue usage. Among the various grammatical cues, learners showed a marked preference for inflections (i.e. gender and number). The use of semantic cues was also common (32%), but led to word class confusions when learners knew only the general meaning of a target word but not the exact L1 equivalent. Finally, an error analysis indicates that the main problem for these learners may not be misclassification of lexical items but rather incomplete syntactic knowledge.

Cognitively-engineered multisensor image fusion for military applications

The fusion of imagery from multiple sensors is a field of research that has been gaining prominence in the scientific community in recent years. The technical aspects of combining multisensory image information have been and are currently being studied extensively. However, the cognitive aspects of multisensor image fusion have not received as much attention. In this study, a concurrent protocol procedure was used to identify how humans fuse information from visible and infrared imagery in low- and high-stress situations. The results of the concurrent protocol were used to develop operator function models, which were then used to develop preliminary design points for fusing multisensor image data. Fused image data were then used in a combat/target identification simulation, and operator performance, accuracy, and speed were compared with results obtained using unfused data. The results show that the model is an accurate depiction of how humans interpret information from multiple disparate sensors in this particular scenario, and that the algorithm design points show promise for assisting fighter pilots in quicker and more accurate target identification.

Latent Handover: A flow-oriented progressive handover mechanism

The next generation network may be regarded as an IP (Internet Protocol) converged network, combining various access technologies. In this environment, ubiquitous computing and seamless networking are required for the mobile host. The growing availability of multiple network interfaces on mobile devices makes Concurrent Multi-path Transfer (CMT) an appealing candidate to realize the seamless handover. In this paper, we proposed a novel Latent Handover mechanism, which is flow-oriented and switches the traffic to the new path progressively to make the handover process unconscious to users or upper layer applications, especially real-time services. In addition, to support the proposed Latent Handover, the transport layer introduces our proposed cmpSCTP (concurrent multi-path Stream Control Transmission Protocol), which adds concurrent multi-path transfer and dynamic Multi-Path Management support to the standard SCTP for realizing seamless handover. The theoretical analysis verified that the proposed Latent Handover can efficiently optimize the handover process and enhance transmission efficiency during handover. Extensive simulations under different scenarios using OPNET highlighted the superiority of the proposed Latent Handover solution against other existing handover schemes under performance indexes such as throughput, handover latency, packet delay, and packet loss.

Service‐Oriented Synthesis of Distributed and Concurrent Protocol Specifications

Several methods have been proposed for synthesizing computer communication protocol specifications from service specifications. Some protocol synthesis methods based on the finite state machine (FSM) model assume that primitives in the service specifications cannot be executed simultaneously. Others either handle only controlled primitive concurrency or have tight restrictions on the applicable FSM topologies. As a result, these synthesis methods are not applicable to an interesting variety of inherently concurrent applications, such as the Internet and mobile communication systems. This paper proposes a concurrent‐based protocol synthesis method that eliminates the restrictions imposed by the earlier methods. The proposed method uses a synthesis method to obtain a sequential protocol specification (P‐SPEC) from a given service specification (S‐SPEC). The resulting P‐SPEC is then remodeled to consider the concurrency behavior specified in the S‐SPEC, while guaranteeing that P‐SPEC provides the specified service.

Architecture of the Scalable Communications Core's Network on Chip

The SCC is a flexible and energy-and area-efficient baseband processor for concurrent multiple wireless protocols. Its architecture consists of coarse grained, heterogeneous, programmable accelerators connected via a packet-based, 3-ary 2-cube network on chip. The NOC supports goals of flexibility, scalability, and extensibility, and it meets stringent latency and throughput requirements.

Architecture of the Scalable Communications Core's Network on Chip

The SCC is a flexible and energy- and area-efficient baseband processor for concurrent multiple wireless protocols. Its architecture consists of coarse-grained, heterogeneous, programmable accelera...

Update on neoadjuvant strategies for rectal cancer patients

Neoadjuvant treatment is becoming the standard for T3-4 (distal T2) rectal adenocarcinoma. Phase III ongoing clinical trials will yield the definition of optimal concurrent chemoradiotherapy protocol. Phase II trials will test new medical treatments (targeted biotherapy) and innovative radiation technique (contact radiotherapy). Most importantly, phase II and III trials will address the question of new strategies using neoadjuvant approach to improve conservative treatment and survival rates.

The reactive simulatability (RSIM) framework for asynchronous systems

We define reactive simulatability for general asynchronous systems. Roughly, simulatability means that a real system implements an ideal system (specification) in a way that preserves security in a general cryptographic sense. Reactive means that the system can interact with its users multiple times, e.g., in many concurrent protocol runs or a multi-round game. In terms of distributed systems, reactive simulatability is a type of refinement that preserves particularly strong properties, in particular confidentiality. A core feature of reactive simulatability is composability, i.e., the real system can be plugged in instead of the ideal system within arbitrary larger systems; this is shown in follow-up papers, and so is the preservation of many classes of individual security properties from the ideal to the real systems. A large part of this paper defines a suitable system model. It is based on probabilistic IO automata (PIOA) with two main new features: One is generic distributed scheduling. Important special cases are realistic adversarial scheduling, procedure-call-type scheduling among colocated system parts, and special schedulers such as for fairness, also in combinations. The other is the definition of the reactive runtime via a realization by Turing machines such that notions like polynomial-time are composable. The simple complexity of the transition functions of the automata is not composable. As specializations of this model we define security-specific concepts, in particular a separation between honest users and adversaries and several trust models. The benefit of IO automata as the main model, instead of only interactive Turing machines as usual in cryptographic multi-party computation, is that many cryptographic systems can be specified with an ideal system consisting of only one simple, deterministic IO automaton without any cryptographic objects, as many follow-up papers show. This enables the use of classic formal methods and automatic proof tools for proving larger distributed protocols and systems that use these cryptographic systems.

A Proof of Revised Yahalom Protocol in the Bellare and Rogaway (1993) Model

Although the Yahalom protocol, proposed by Burrows, Abadi, and Needham in 1990, is one of the most prominent key establishment protocols analysed by researchers from the computer security community (using automated proof tools), a simplified version of the protocol is only recently proven secure by Backes and Pfitzmann [(2006) On the Cryptographic Key Secrecy of the Strengthened Yahalom Protocol. Proc. IFIP SEC 2006] in their cryptographic library framework. We present a protocol for key establishment that is closely based on the Yahalom protocol. We then present a security proof in the Bellare, M. and Rogaway, P. [(1993a). Entity Authentication and Key Distribution. Proc. of CRYPTO 1993, Santa Barbara, CA, August 22–26, LNCS, Vol. 773, pp. 110–125. Springer-Verlag, Berlin] model and the random oracle model. We also observe that no partnering mechanism is specified within the Yahalom protocol. We then present a brief discussion on the role and the possible construct of session identifiers (SIDs) as a form of partnering mechanism, which allows the right session key to be identified in concurrent protocol executions. We then recommend that SIDs should be included within protocol specification rather than consider SIDs as artefacts in protocol proof.

Universally Composable Security Concurrent Deniable Authentication Based on Witness Indistinguishable

A new approach and an idea for exploration are presented to the concurrent deniable authentication based on witness-indistinguishable (WI) within the framework of universally composable (UC) security. A definition of an ideal functionality for deniable authentication is formulated. A new deniable authentication protocol is proposed based on two primitives of the verifiably smooth projective Hashing (VSPH) and non-committing encryptions (NCE). This new approach is practically relevant to VSPH based on the Decisional Diffie-Hellman (DDH) assumption and NCE based on the decisional composite residuosity (DCR) assumption. Compared with a timing constraint and public directory model, simulation of the concurrent protocols is not needed to restrict an adversary capability in a common reference string (CRS) model. The protocols are forward deniable and UC security against adaptive adversaries. Unlike previous proposals with the CCA2 public-key cryptosystem or multi-trapdoor commitments paradigm, the new paradigm leads to more efficient protocols.

TPF induction chemotherapy followed by concurrent radiochemotherapy in the first line therapy of advanced carcinomas of the larynx and pharynx (phase IIb trial)

5562 Backround: Concurrent radiochemotherapy has become a standard procedure for the organ preservation treatment of advanced laryngeal cancer. According to the RTOG 91–11 protocol 2 years larynx preservation and disease free survival rates of 88% and 61% have been described (N Engl J Med 2003;349:2091–8). We perform a phase IIb study answering the question if the addition of triple induction therapy with docetaxel, cisplation and 5FU (TPF) to this regimen is feasible and able to enhance larynx preservation and the disease free survival. Methods: Eligibility criteria have been untreated measurable (RECIST) Stage III/IV carcinomas of the larynx and pharynx in ECOG 0–2 pts. with sufficient organ functions. Planned treatment consisted of 3 cycles induction chemotherapy (every 3 weeks) with docetaxel 75 mg/m2/d1, cisplatin 100 mg/m2/d1 and 5 Fluorouracil 1000 mg/m2/d1–4 (TPF) followed by concurrent radiochemotherapy according to the RTOG 91–11 protocol. Controls have been treated with concurrent radiochemotherapy (RTOG 91–11). One stage design, primary endpoint is recurrence free survival, planned sample size is 250 with 192 events to have a power of 80% to detect a relative risk = 1,432 using a one sided test, alfa = 0.05. Results: 103 patients have been evaluated up to know. Completion of therapy was equivalent in both groups (1/5 drop out rate). Main grade 3/4 toxicities (CTC) during induction chemotherapy were neutropenia (95%) and renal toxicity (25%) and during chemoradiation mucositis (40%) in the chemoradiation group and mucositis (43%), neutropenia (46%) and renal toxicties (24%) in the induction chemotherapy group The toxicities were reversible. After induction chemotherapy the ORR was 84% with a CR of 55%. After the completion of therapy the ORR in the induction chemotherapy group (IC) was 97% versus 93% in the chemoradiation group (RC). After a median follow up of two years the larynx preservation rates and the disease free survival rates are as follows:91% (IC) vs. 87% (CR), n.s., and 85% (IC) vs. 66% (RC), p = 0.017. Conclusion: Addition of TPF induction therapy to the RTOG 91–11 concurrent radiochemotherapy protocol may enhance the disease free survival. No significant financial relationships to disclose.

Real-or-random Key Secrecy of the Otway-Rees Protocol via a Symbolic Security Proof

We present the first cryptographically sound security proof of the well-known Otway-Rees protocol. More precisely, we show that the protocol is secure against arbitrary active attacks including concurrent protocol runs if it is implemented using provably secure cryptographic primitives. We prove secrecy of the exchanged keys with respect to the accepted cryptographic definition of real-or-random secrecy, i.e., indistinguishability of exchanged keys and random ones, given the view of a general cryptographic attacker. Although we achieve security under cryptographic definitions, our proof is performed in a deterministic setting corresponding to a slightly extended Dolev-Yao model; in particular, it does not have to deal with probabilistic aspects of cryptography and is hence in the scope of current proof tools. The reason is that we exploit a recently proposed ideal cryptographic library, which has a provably secure cryptographic implementation, as well as recent results on linking symbolic and cryptographic key secrecy. Besides establishing the cryptographic security of the Otway-Rees protocol, our result also exemplifies the potential of this cryptographic library and the recent secrecy preservation theorem for symbolic yet cryptographically sound proofs of security.

ZD6474, a Potent Inhibitor of Vascular Endothelial Growth Factor Signaling, Combined With Radiotherapy

Abstract Purpose: Vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis and acts as a radiation survival factor for endothelial cells. ZD6474 (N-(4-bromo-2-fluorophenyl)-6-methoxy-7-[(1-methylpiperidin-4-yl)methoxy]quinazolin-4-amine) is a potent VEGF receptor 2 (KDR) tyrosine kinase inhibitor (TKI) that has additional activity versus the epidermal growth factor receptor. This study was designed to determine the efficacy of combining ZD6474 and radiotherapy in vivo. Experimental Design: The Calu-6 (non–small-cell lung cancer) tumor model was selected because it was found to be unresponsive to treatment with a selective epidermal growth factor receptor TKI but responds significantly to treatment with selective VEGF receptor TKIs. Tumor-bearing mice received either vehicle or ZD6474 (50 mg/kg, by mouth, once daily) for the duration of the experiment, with or without radiotherapy (3 × 2 Gy, days 1–3). Two combination schedules were examined: (a) ZD6474 given before each dose of radiation (concurrent schedule); and (b) ZD6474 given 30 minutes after the last dose of radiotherapy (sequential schedule). Results: The growth delay induced using the concurrent schedule was greater than that induced by ZD6474 or radiation treatment alone (22 ± 1 versus 9 ± 1 and 17 ± 2 days, respectively; P = 0.03 versus radiation alone). When administered sequentially, the growth delay was markedly enhanced (36 ± 1 days; P < 0.001 versus radiation alone or the concurrent schedule). Intravenous administration of Hoechst 33342 showed a trend toward reduced tumor perfusion after ZD6474 treatment, and a pairwise comparison (versus control) was significant after three doses of ZD6474 (P = 0.05 by one-tailed t test). Thus, impaired reoxygenation between fractions in the concurrent protocol may be the causal basis for the schedule dependency of the radiopotentiation observed. Conclusions: ZD6474 may be a successful adjuvant to clinical radiotherapy, and scheduling of the treatments could be important to ensure optimal efficacy.

The Role of Myth in Creative Advertising Design: Theory, Process and Outcome

In an empirical study using five real-world creative teams from an advertising agency, participants were given a strategic brief for a new beverage product and asked to design the layout for a print ad. Think-aloud concurrent protocols obtained from each team's copywriter, art director, and the two working together were analyzed to examine the creative process and its relationship to the created advertisement. Interpretive analyses of the protocols reveal that the teams access culturally available plot patterns but in different ways. In this study and with the particular materials and situational context explored here, four of the five teams chose to pursue a single mythic structure to the apparent detriment of their final product. Only one team engaged in fully diversified idea generation involving a wide range of alternative scenarios. Not coincidentally, as a tentative conclusion, this more flexible team produced the ad judged most successful by advertising professionals. This still-to-be-tested exploratory finding deserves further investigation in future research that embodies various methodological refinements.