ブドウ‘マスカット・オブ・アレキサンドリア’に対する潅水制限が樹体の水分，葉温，果実温，果実の全フェノール含量，果皮色に及ぼす影響

　Effects of different deficit irrigation strategies on vine water status, canopy and cluster temperatures, fruit total phenolics, and the color of white table grapes (Vitis vinifera L., cv. Muscat of Alexandria) were compared to a well-irrigated control in 2004 from veraison to harvest at the Okayama University Experimental Vineyard, Japan. The treatments included: (1) well-irrigated control: re-irrigation when the soil moisture tension reached 15 kPa; (2) regulated deficit irrigation (RDI): re-irrigation 4 to 7 days after reaching a soil moisture tension of 15 kPa; (3) fixed partial root-zone wetting (FPRW): one part of the root system was re-irrigated when the soil moisture tension reached 15 kPa; and (4) alternate partial root-zone wetting (APRW): one part of the root system was re-irrigated when the soil moisture tension reached 15 kPa, and every week the irrigated part was switched. As the stress developed in RDI vines, leaf water potential and transpiration rate decreased and canopy and cluster temperatures increased as compared with the control. In contrast, both FPRW and APRW vines had similar leaf water potential and canopy and cluster temperatures, but less leaf transpiration rate as compared with the control. At harvest, fruits from all treatments had higher skin total phenolics and CIELAB a＊ values than the control. RDI fruit had higher total soluble solids (TSS), a similar acidity, and smaller size compared with the control. FPRW and APRW fruits had slightly higher TSS, lower acidity, and a similar size compared with the control.ベレゾーン期から収穫期までの潅水制限処理が‘マスカット・オブ・アレキサンドリア’ブドウ（Vitis vinifera L｡）の水分条件，葉温，果実温，果実の全フェノール，果皮色に及ぼす影響を，十分に潅水した樹と比較した．実験は2004年に岡山大学農学部内の実験圃場で行った．処理区は，１) 土壌水分張力が15kPa に達したときに潅水する対照区，２) 土壌水分張力が15kPa に達してから４～７日後に潅水する制限潅水区，３) 土壌水分張力が15kPa に達したときに根域の半分に潅水する片側潅水区，４) 片側潅水する根域部分を１週間ごとに変更する交互潅水区とした．制限潅水区では水分ストレスが強まるにつれて葉の水ポテンシャルと蒸散速度が対照区よりも低下し，果実温が高くなった．しかし，片側潅水区と交互潅水区では，葉の水ポテンシャルと葉温，果実温は対照区と同程度で，蒸散速度が低下した．収穫期の果皮の全フェノールと CIELAB a＊ 値は，潅水を制限した各区では標準区より高かった．制限潅水区の果実は，標準区より糖度が高く，酸度は低く，果粒は小さかった．片側潅水区，交互潅水区では糖度がやや高く，酸度は低く，果粒の大きさは同程度であった

NATCracker: NAT Combinations Matter

In this paper, we report our experience in working with Network Address Translators (NATs). Traditionally, there were only 4 types of NATs. For each type, the (im)possibility of traversal is well-known. Recently, the NAT community has provided a deeper dissection of NAT behaviors resulting into at least 27 types and documented the (im)possibility of traversal for some types. There are, however, two fundamental issues that were not previously tackled by the community. First, given the more elaborate set of behaviors, it is incorrect to reason about traversing a single NAT, instead combinations must be considered and we have not found any study that comprehensively states, for every possible combination, whether direct connectivity with no relay is feasible. Such a statement is the first outcome of the paper. Second, there is a serious need for some kind of formalism to reason about NATs which is a second outcome of this paper. The results were obtained using our own scheme which is an augmentation of currently-known traversal methods. The scheme is validated by reasoning using our formalism, simulation and implementation in a real P2P network

Physics-inspired Performace Evaluation of a Structured Peer-to-Peer Overlay Network

In the majority of structured peer-to-peer overlay networks a graph with a desirable topology is constructed. In most cases, the graph is maintained by a periodic activity performed by each node in the graph to preserve the desirable structure in face of the continuous change of the set of nodes. The interaction of the autonomous periodic activities of the nodes renders the performance analysis of such systems complex and simulation of scales of interest can be prohibitive. Physicists, however, are accustomed to dealing with scale by characterizing a system using intensive variables, i.e. variables that are size independent. The approach has proved its usefulness when applied to satisfiability theory. This work is the first attempt to apply it in the area of distributed systems. The contribution of this paper is two-fold. First, we describe a methodology to be used for analyzing the performance of large scale distributed systems. Second, we show how we applied the methodology to find an intensive variable that describe the characteristic behavior of the Chord overlay network, namely, the ratio of the magnitude of perturbation of the network (joins/failures) to the magnitude of periodic stabilization of the network

Underlying structures of risk response measures among small and medium contractors in South Africa

Although attention has been given to the measures used to respond to risk in the construction industry (CI), there is limited literature that scrutinizes underlying structures of risk response measures (RRMs) especially among small and medium enterprises (SMEs). This study, therefore, presents findings from an exploratory factor analysis (EFA) of RRMs. A positivist paradigm was adopted to collect empirical raw data from 181 conveniently sampled respondents in Gauteng, South Africa (SA), using a structured questionnaire. The results support the extant literature and empirically established the structural composition of risk response by two constructs. The construct with emerged measures was termed trailing measures while the one with popular measures was termed leading measures of risk response. However, the study yielded a two-factor model with all the six items supposed to measure risk response. Based on the results obtained, it seems that risk avoidance and risk mitigation are reliable measures for measuring risk response. This study could thus serve as a reference for the accurate measurement of risk response and for the development of agreed responses for each risk, including an appropriate strategy and specific responses to implement the chosen strategy. The study was limited to the CI and to a lesser extent, construction SMEs in Gauteng; hence the findings cannot be generalized to all SMEs in SA

An Analytical Study of a Structured Overlay in the presence of Dynamic Membership

In this paper, we present a complete analytical study of dynamic membership (aka churn) in structured peer-to-peer networks. We use a master-equation-based approach, which is used traditionally in non-equilibrium statistical mechanics to describe steady-state or transient phenomena. We demonstrate that this methodology is in fact also well suited to describing structured overlay networks by an application to the Chord system. For any rate of churn and stabilization rates, and any system size, we accurately account for the functional form of: the distribution of inter-node distances, the probability of network disconnection, the fraction of failed or incorrect successor and finger pointers and show how we can use these quantities to predict both the performance and consistency of lookups under churn. Additionally, we also discuss how churn may actually be of different 'types' and the implications this will have for structured overlays in general. All theoretical predictions match simulation results to a high extent. The analysis includes details that are applicable to a generic structured overlay deploying a ring as well as Chord-specific details that can act as guidelines for analyzing other systems

Mesmerizer: A Effective Tool for a Complete Peer-to-Peer Software Development Life-cycle

In this paper we present what are, in our experience, the best practices in Peer-To-Peer(P2P) application development and how we combined them in a middleware platform called Mesmerizer. We explain how simulation is an integral part of the development process and not just an assessment tool. We then present our component-based event-driven framework for P2P application development, which can be used to execute multiple instances of the same application in a strictly controlled manner over an emulated network layer for simulation/testing, or a single application in a concurrent environment for deployment purpose. We highlight modeling aspects that are of critical importance for designing and testing P2P applications, e.g. the emulation of Network Address Translation and bandwidth dynamics. We show how our simulator scales when emulating low-level bandwidth characteristics of thousands of concurrent peers while preserving a good degree of accuracy compared to a packet-level simulator

An Analytical Study of a Structured Overlay in the presence of Dynamic Membership

In this paper we present an analytical study of dynamic membership (aka churn) in structured peer-to-peer networks. We use a fluid model approach to describe steady-state or transient phenomena, and apply it to the Chord system. For any rate of churn and stabilization rates, and any system size, we accurately account for the functional form of the probability of network disconnection as well as the fraction of failed or incorrect successor and finger pointers. We show how we can use these quantities to predict both the performance and consistency of lookups under churn. All theoretical predictions match simulation results. The analysis includes both features that are generic to structured overlays deploying a ring as well as Chord-specific details, and opens the door to a systematic comparative analysis of, at least, ring-based structured overlay systems under churn.Comment: 12 pages, 14 figures, to appear in IEEE/ACM Transactions on Networkin

Multicast in DKS(N, k, f) Overlay Networks

Recent developments in the area of peer-to-peer computing show that structured overlay networks implementing distributed hash tables scale well and can serve as infrastructures for Internet scale applications. We are developing a family of infrastructures, DKS(N; k; f), for the construction of peer-to-peer applications. An instance of DKS(N; k; f) is an overlay network that implements a distributed hash table and which has a number of desirable properties: low cost of communication, scalability, logarithmic lookup length, fault-tolerance and strong guarantees of locating any data item that was inserted in the system. In this paper, we show how multicast is achieved in DKS(N, k, f) overlay networks. The design presented here is attractive in three main respects. First, members of a multicast group self-organize in an instance of DKS(N, k, f) in a way that allows co-existence of groups of different sizes, degree of fault-tolerance, and maintenance cost, thereby, providing flexibility. Second, each member of a group can multicast, rather than having single source multicast. Third, within a group, dissemination of a multicast message is optimal under normal system operation in the sense that there are no redundant messages despite the presence of outdated routing information