Cognitive optimism of distinctive initiatives to foster self-directed and self-regulated learning skills:A comparative analysis of conventional and blended-learning in undergraduate studies

Independent learning in massive open online courses (MOOCs) requires considerable effort from the learners themselves. Blended-learning has been recognised to foster independent learning among undergraduate students. With the popularity of the blended-learning approach to teach in traditional educational settings, little has been mentioned on how cohesive this approach is in fostering self-directed learning and self-regulation among university students. This study hopes to explore undergraduate learners in their distinctive study patterns. The study was conducted to investigate a comparative study between students from two departments; Science and Social Science. The aim was to explore the students’ self-directed and self-regulated learning skills in conventional classrooms and aspects of blended-learning embedded in a MOOC platform in two academic years for undergraduates at a top UK university. This study encompasses two case studies; firstly, a combine blended-learning seminar and a conventional seminar classes and a study undertaken with a student of English as a second language (ESL). The blended-learning students were participants who registered in a conventional university and took an optional module in computer security. The second group of students participated in a core module of logic and verification. The second case study was with a final year undergraduate student in Education Studies. The students studied and engaged with the course content using their initiative and directing their learning approaches

High performance deferred update replication

Replication is a well-known approach to implementing storage systems that can tolerate failures. Replicated storage systems are designed such that the state of the system is kept at several replicas. A replication protocol ensures that the failure of a replica is masked by the rest of the system, in a way that is transparent to its users. Replicated storage systems are among the most important building blocks in the design of large scale applications. Applications at scale are often deployed on top of commodity hardware, store a vast amount of data, and serve a large number of users. The larger the system, the higher its vulnerability to failures. The ability to tolerate failures is not the only desirable feature in a replicated system. Storage systems need to be efficient in order to accommodate requests from a large user base while achieving low response times. In that respect, replication can leverage multiple replicas to parallelize the execution of user requests. This thesis focuses on Deferred Update Replication (DUR), a well-established database replication approach. It provides high availability in that every replica can execute client transactions. In terms of performance, it is better than other replication techniques in that only one replica executes a given transaction while the other replicas only apply state changes. However, DUR suffers from the following drawback: each replica stores a full copy of the database, which has consequences in terms of performance. The first consequence is that DUR cannot take advantage of the aggregated memory available to the replicas. Our first contribution is a distributed caching mechanism that addresses the problem. It makes efficient use of the main memory of an entire cluster of machines, while guaranteeing strong consistency. The second consequence is that DUR cannot scale with the number of replicas. The throughput of a fully replicated system is inherently limited by the number of transactions that a single replica can apply to its local storage. We propose a scalable version of the DUR approach where the system state is partitioned in smaller replica sets. Transactions that access disjoint partitions are parallelized. The last part of the thesis focuses on latency. We show that the scalable DUR-based approach may have detrimental effects on response time, especially when replicas are geographically distributed. The thesis considers different deployments and their implications on latency. We propose optimizations that provide substantial gains in geographically distributed environments

Robust force sensing for a free particle in a dissipative optomechanical system with a parametric amplifier

We theoretically investigate optical detection of a weak classical force acting on a free particle in a dissipative coupling optomechanical system with a degenerate parametric amplifier (PA). We show that the PA allows one to achieve the force sensitivity far better than the standard quantum limit (SQL) over a broad range of the detection frequencies. The improvement depends on the parametric gain and the driving power. Moreover, we discuss the effects of the mechanical damping and the thermal noise on the force sensitivity. We find that the robustness of the force sensitivity much better than the SQL against the mechanical damping and the thermal noise is achievable in the presence of the PA with a high parametric gain. For the temperature $T = 1$ K, the improvement in sensitivity is better by a factor of about 7 when the driving power is set at a value corresponding to the SQL with no PA.Comment: 10 pages, 6 figures, 2 table

長崎市の飼い犬の飼育環境と人畜共通寄生虫，犬糸状虫の予防の実態に関するアンケート調査

犬糸状虫の感染と犬の飼育環境や飼い主の予防の実施の有無との関連性の手がかりをつかむため，1989年と1993年に長崎市の南部の戸町地区と北部の坂本，高尾，山里の3地区の320名または397名の飼い主を対象に犬の飼育環境と予防の実態についてアンケート調査を実施した．1989年と1993年の回収率はそれぞれ65.9％または55.9％であった．感染率の低い北部3 地区では家の中で犬を飼うと答えた人が多かった．感染率の高い南部の1地区では庭で犬を飼う人が多かった．このことから南部の犬は北部の犬に比べて主要伝搬蚊であるアカイエカに刺される機会が多くなることが推測される．予防措置としてはどの地区でも蚊取り線香が高頻度に使われていることがわかった．予防薬を投与している飼い主は一般に少なかった．To examine the role of living environments of domestic dogs and the measures taken by dogs owners to protect their dogs in the prevention of Dirofilaria immitis infection, we carried out a questionnaire survey in Tomachi (from the southern part of Nagasaki City) and Sakamoto, Takao and Yamazato (from the northern part of the same city) in 1989 (for 320 dog owners) and 1993 (for 397 owners). The percentage of dog owners who answered to the questionnaire was 65.9% in 1989 and 55.9% in 1993. In the northern 3 districts where positive rates the percentage of larvae-carrying dogs were low, dogs were often kept indoors. In the southern district (Tomachi) where the positive rate was high, dogs were often kept outdoors (in the yard). The high percentage of dogs kept outdoors in Tomachi seems to have increased the exposure of dogs to main vector mosquito, Cx. p. pallens. In all districts, mosquito-repellent coils were most frequently used as a means to control mosquitoes. The percentage of dog owners who used preventive drugs tended to be low

Building global and scalable systems with atomic multicast

The rise of worldwide Internet-scale services demands large distributed systems. Indeed, when handling several millions of users, it is common to operate thousands of servers spread across the globe. Here, replication plays a central role, as it contributes to improve the user experience by hiding failures and by providing acceptable latency. In this thesis, we claim that atomic multicast, with strong and well-defined properties, is the appropriate abstraction to efficiently design and implement globally scalable distributed systems. Internet-scale services rely on data partitioning and replication to provide scalable performance and high availability. Moreover, to reduce user-perceived response times and tolerate disasters (i.e., the failure of a whole datacenter), services are increasingly becoming geographically distributed. Data partitioning and replication, combined with local and geographical distribution, introduce daunting challenges, including the need to carefully order requests among replicas and partitions. One way to tackle this problem is to use group communication primitives that encapsulate order requirements. While replication is a common technique used to design such reliable distributed systems, to cope with the requirements of modern cloud based ``always-on'' applications, replication protocols must additionally allow for throughput scalability and dynamic reconfiguration, that is, on-demand replacement or provisioning of system resources. We propose a dynamic atomic multicast protocol which fulfills these requirements. It allows to dynamically add and remove resources to an online replicated state machine and to recover crashed processes. Major efforts have been spent in recent years to improve the performance, scalability and reliability of distributed systems. In order to hide the complexity of designing distributed applications, many proposals provide efficient high-level communication abstractions. Since the implementation of a production-ready system based on this abstraction is still a major task, we further propose to expose our protocol to developers in the form of distributed data structures. B-trees for example, are commonly used in different kinds of applications, including database indexes or file systems. Providing a distributed, fault-tolerant and scalable data structure would help developers to integrate their applications in a distribution transparent manner. This work describes how to build reliable and scalable distributed systems based on atomic multicast and demonstrates their capabilities by an implementation of a distributed ordered map that supports dynamic re-partitioning and fast recovery. To substantiate our claim, we ported an existing SQL database atop of our distributed lock-free data structure. Here, replication plays a central role, as it contributes to improve the user experience by hiding failures and by providing acceptable latency. In this thesis, we claim that atomic multicast, with strong and well-defined properties, is the appropriate abstraction to efficiently design and implement globally scalable distributed systems. Internet-scale services rely on data partitioning and replication to provide scalable performance and high availability. Moreover, to reduce user-perceived response times and tolerate disasters (i.e., the failure of a whole datacenter), services are increasingly becoming geographically distributed. Data partitioning and replication, combined with local and geographical distribution, introduce daunting challenges, including the need to carefully order requests among replicas and partitions. One way to tackle this problem is to use group communication primitives that encapsulate order requirements. While replication is a common technique used to design such reliable distributed systems, to cope with the requirements of modern cloud based ``always-on'' applications, replication protocols must additionally allow for throughput scalability and dynamic reconfiguration, that is, on-demand replacement or provisioning of system resources. We propose a dynamic atomic multicast protocol which fulfills these requirements. It allows to dynamically add and remove resources to an online replicated state machine and to recover crashed processes. Major efforts have been spent in recent years to improve the performance, scalability and reliability of distributed systems. In order to hide the complexity of designing distributed applications, many proposals provide efficient high-level communication abstractions. Since the implementation of a production-ready system based on this abstraction is still a major task, we further propose to expose our protocol to developers in the form of distributed data structures. B- trees for example, are commonly used in different kinds of applications, including database indexes or file systems. Providing a distributed, fault-tolerant and scalable data structure would help developers to integrate their applications in a distribution transparent manner. This work describes how to build reliable and scalable distributed systems based on atomic multicast and demonstrates their capabilities by an implementation of a distributed ordered map that supports dynamic re-partitioning and fast recovery. To substantiate our claim, we ported an existing SQL database atop of our distributed lock-free data structure

SQLToKeyNoSQL: uma camada para mapeamento de esquemas relacionais e de operações SQL para bancos de dados NoSQL baseados em chaves de acesso

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência da Computação, Florianópolis, 2016.Diversas aplicações atualmente produzem e manipulam um grande volume de dados, denominados Big Data. Bancos de dados tradicionais, em particular, os Bancos de Dados Relacionais (BDRs), não são adequados ao gerenciamento de Big Data. Devido a isso, novos modelos de dados têm sido propostos para manipular grandes massas de dados, enfatizando a escalabilidade e a disponibilidade. A maioria destes modelos de dados pertence a uma nova categoria de gerenciadores de dados denominados BDs NoSQL. Entretanto, BDs NoSQL não são compatíveis, em geral, com o padrão SQL e desenvolvedores que utilizam BDRs necessitam aprender novos modelos de dados e interfaces de acesso para produzirem aplicações baseadas em Big Data. Para lidar com esta problemática, abordagens têm sido propostas para o suporte da interoperabilidade entre BDRs e BDs NoSQL. Poucas destas abordagens tem a habilidade de suportar mais que um BD alvo, sendo a maioria restrita a um BD NoSQL. Neste contexto, este trabalho propõe uma abordagem para acesso via SQL para dados armazenados em um SGBD NoSQL baseado em Chave de acesso (chave-valor, orientado a documentos ou orientado a colunas). Para isso, é proposto um modelo canônico hierárquico intermediário para o qual é traduzido o modelo Relacional. Este modelo hierárquico pode ser traduzido para modelos de dados NoSQL orientado a colunas, orientado a documentos ou chave-valor. A tradução das instruções SQL é feita para um conjunto intermediário de métodos baseado na API REST, que são traduzidos para a linguagem de acesso dos BDs NoSQL. Além disso, a abordagem possibilita o processamento de junções que não são suportadas pelos BDs NoSQL. Experimentos demostram que a solução proposta é promissora, possuindo um overhead não proibitivo e sendo competitiva com ferramentas existentes.Abstract : A lot of applications produce and manipulate today a large volume of data, the so-called Big Data. Traditional databases, like relational databases (RDB), are not suitable to Big Data management. In order to deal with this problem, a new category of DB has been proposed, been most of them called NoSQL DB. NoSQL DB have different data models, as well as different access methods which are not usually compatible with the RDB SQL standard. In this context, approaches have been proposed for providing mapping of RDB schemata and operations to equivalent ones in NoSQL DB to deal with large relational data sets in the cloud, focusing on scalability and availability. However, these approaches map relational DB only to a single NoSQL data model and, sometimes, to a specific NoSQL DB product. This work presents SQLToKeyNoSQL, a layer able to translate, in a transparent way, RDB schemata as well as SQL instructions to equivalent schemata and access methods for key-oriented NoSQL DB, i.e., databases based on document-oriented, key-value and column-oriented data models. We propose a hierarchical data model that abstracts the key-oriented NoSQL data models, and use it as an intermediate data model for mapping the relational data model to these NoSQL data models. Besides, we propose the translation of a subset of SQL instructions to an intermediate set of access methods based on the REST API, which are further translated, in a simple way, to the access methods of the key-oriented NoSQL DB. Our solution also supports join queries, which is not a NoSQL DB capability. An experimental evaluation demonstrates that our approach is promising, since the introduced overhead with our layer is not prohibitive

Supplements to the Finding on the Susceptibility of Japanese Mosquitoes to Wuchereria bancrofti. : 2. On the susceptibility of Anopheles hyrcanus sinensis and Culex tritaeniorhynchus.

1)著者は1955年11月から1957年6月迄の間にAnopheles hyrcanus sinensisとCulex tritaeniorhynchusについてWuchereria bancroftiの感染実験を行つて次の成績を得た.2) Anopheles hyrcanus sinensisについては13回に亘つて合計339個体の感染血摂取蚊を剖検した結果,大多数の幼虫は発育の極く初期即ちIbの時期に死亡しやがてキチン化される.僅少個体のみがII期に進むが,III期に到達できるものはない.著者のこの成績は,福岡で行なつた望月(1911)の成績とよく一致するが,東京で行なつた山田(1927)の成績とは可成りに相異している.山田によると約4.6%の幼虫は感染幼虫となると報告されている.この実験結果の喰い違いの原因は不明であるが,著者の成績は各種飼育温度で多数の蚊について実験した結果であり,望月のかつての成績とよく一致するので少なくとも九州ではシナハマダラカは中間宿主として不適当な種類であると断定し疫学的には全く意味のないものと考えてもよいように思う.3)Culex tritaeniorhychusについては4回に亘り感染血を摂放した206個体の蚊を剖検した結果,この蚊の体内ではフイラリア幼虫はId即ち第1回目の脱皮直前迄は発育できるがこの時期に多くの個体が宿主体内で殺される.然し若干個体はII期に進み,僅小個体は感染幼虫となる.感染幼虫となる個体数の割合は約4.7%であり,感染幼虫を保有した蚊は剖検蚊の約4.9%である.この成績を山田及び望月の結果と比較すると,著者の成績では感染幼虫となる比率が多少低いが,可成りによく一致する.即ち本種体内では僅少個体ではあるが感染幼虫に到達できる.然し本種も動物嗜好性が寧ろ強く,又,吸血量が少ないので摂取する幼虫数も平均的には少ないであろう事が考えられ,疫学的には殆んど問題とはならないものと考えられる.Studies of the susceptibility of A. hyrcanus sinensis and Culex tritaeniorhynchus to Wuchereria bancrofti were carried out from 1955 to 1957. These mosquitoes are breeding in rice field and drains in the field and widely distributed but not so abundant i