The role of the first language in second language learning for adult learners : a Vygotskian perspective

University of Technology, Sydney. Faculty of Education.The purpose of the present study is to provide a view of the second language learning process, in which the first language (LI) was used for second language learning (L2). Through data collected in authentic classrooms from two groups of learners, Level One and Level Two, it is hoped that the present study will provide insight, which will enable teachers and researchers who are interested in second language development to see how adult L2 learners used their LI in L2 learning. The study also sheds light on the way adult learners perceive their use of LI for L2 learning. The first language has long been regarded as ‘interference’, playing a negative role. Research and theories in the past focused on the problems caused by the first language in the second language learning. With the notion of ‘English only’ in the ESL classroom, not many teachers allowed the use of LI in L2 classrooms, and little research has been conducted to determine how LI could contribute towards L2 learning. Although more recent research suggests that the first language can be a resource, not many significant studies focus on exactly how adult learners make use of their first language in second language learning, and what significance it has for adult second language learning. In reality, adult learners have access to their first language when they leam the second language, and they make use of LI as a tool to help understand the L2 and to build into their L2 learning. That is to say, there is a discrepancy between theory and practice, and the present study addresses this discrepancy. The present study attempts to look at the role of the first language from a different perspective, a Vygotskian perspective. The theory of Vygotsky (1962), a sociocultural theory that is based on the concept that human activities take place in cultural contexts that are mediated by language and other symbol systems, provides a comprehensive framework for considering the use of LI in L2 learning. Cook (1999), though with a different perspective from that of Vygotsky, regards L2 learners as speakers in their own right and suggests exploiting the students’ LI. Cook’s idea provides an illuminating way of seeing the LI use. Using tape-recorded classroom discourse data from the authentic second language classroom and interviews with learners from two different groups, the present study suggests that LI plays a complex role in L2 learning. This complex role, with support of data from the present study, comprises the use of LI for active construction of knowledge; the use of LI as a tool for thinking and learning; and the use of LI for support and encouragement. Apart from playing a complex role, this study concludes that the role of the first language goes beyond the translation of L2, and using LI does not necessarily imply a lack of competence in L2. Data suggest that adult learners use LI to define, to dispute and to compare the L2 language. LI is like a useful tool which helps to obtain deep knowledge and profound understanding in L2 learning. Data also suggest that adult learners use LI when they need it, and they may not achieve the same degree of learning without LI use. Based on the data, the present study draws some implications for teaching and learning. These include the need for teachers to be positive about the use of LI in L2 learning; to acknowledge and respect the second language learner’s first language; to consider the need of LI use and make appropriate plan to incorporate LI into L2 learning; and researchers need to note that what the learners say can be different from what they do. Finally, the present study has made some recommendations for further studies. The present study suggests firstly, to use authentic classroom data; secondly, to extend the study of LI to other ESL classrooms; and thirdly, to compare and find out various strategies of LI use for various classrooms

Generalized parallelization methodology for video coding

This paper describes a generalized parallelization methodology for mapping video coding algorithms onto a multiprocessing architecture, through systematic task decomposition, scheduling and performance analysis. It exploits data parallelism inherent in the coding process and performs task scheduling base on task data size and access locality with the aim to hide as much communication overhead as possible. Utilizing Petri-nets and task graphs for representation and analysis, the method enables parallel video frame capturing, buffering and encoding without extra communication overhead. The theoretical speedup analysis indicates that this method offers excellent communication hiding, resulting in system efficiency well above 90%. A H.261 video encoder has been implemented on a TMS320C80 system using this method, and its performance was measured. The theoretical and measured performances are similar in that the measured speedup of the H.261 is 3.67 and 3.76 on four PP for QCIF and 352×240 video, respectively. They correspond to frame rates of 30.7 frame per second (fps) and 9.25 fps, and system efficiency of 91.8% and 94% respectively. As it is, this method is particularly efficient for platforms with small number of parallel processors.published_or_final_versio

Parallelization of the H.261 video coding algorithm on the IBM SP2(R) multiprocessor system

In this paper, the parallelization of the H.261 video coding algorithm on the IBM SP2 multiprocessor system is described. Based on domain decomposition as a framework, data partitioning, data dependencies and communication issues are carefully assessed. From these, two parallel algorithms were developed with the first one maximizes on processor utilization and the second one minimizes on communications. Our analysiis shows that the first algorithm exhibits poor scalability and high communication overhead; and the second algorithm exhibits good scalability and low communication overhead. A best median speed up of 13.72 or 11 frameskec was achieved on 24 processors.published_or_final_versio

Spatial and temporal data parallelization of the H.261 video coding algorithm

In this paper, the parallelization of the H.261 video coding algorithm on the IBM SP2 multiprocessor system is described. The effect of parallelizing computations and communications in the spatial, temporal, and both spatial-temporal domains are considered through the study of frame rate, speedup, and implementation efficiency, which are modeled and measured with respect to the number of nodes (n) and parallel methods used. Four parallel algorithms were developed, of which the first two exploited the spatial parallelism in each frame, and the last two exploited both the temporal and spatial parallelism over a sequence of frames. The two spatial algorithms differ in that one utilizes a single communication master, while the other attempts to distribute communications across three masters. On the other hand, the spatial-temporal algorithms use a pipeline structure for exploiting the temporal parallelism together with either a single master or multiple masters. The best median speedup (frame rate) achieved was close to 15[15 frames per second (fps)] for 352 × 240 video on 24 nodes, and 13 (37 fps) for QCIF video, by the spatial algorithm with distributed communications. For n 10, with efficiency up to 70%. The spatial-temporal algorithms achieved average speedup performance, but are most scalable for large n.published_or_final_versio

Generalized parallelization methodology for video coding

This paper describes a generalized parallelization methodology for mapping video coding algorithms onto a multiprocessing architecture, through systematic task decomposition, scheduling and performance analysis. It exploits data parallelism inherent in the coding process and performs task scheduling base on task data size and access locality with the aim to hide as much communication overhead as possible. Utilizing Petri-nets and task graphs for representation and analysis, the method enables parallel video frame capturing, buffering and encoding without extra communication overhead. The theoretical speedup analysis indicates that this method offers excellent communication hiding, resulting in system efficiency well above 90%. A H.261 video encoder has been implemented on a TMS320C80 system using this method, and its performance was measured. The theoretical and measured performances are similar in that the measured speedup of the H.261 is 3.67 and 3.76 on four PP for QCIF and 352×240 video, respectively. They correspond to frame rates of 30.7 frame per second (fps) and 9.25 fps, and system efficiency of 91.8% and 94% respectively. As it is, this method is particularly efficient for platforms with small number of parallel processors.published_or_final_versio

Novel neighborhood search for multiprocessor scheduling with pipelining

Presents a neighborhood search algorithm for heterogeneous multiprocessor scheduling in which loop pipelining is used to exploit parallelism between iterations. The method adopts a realistic model for interprocessor communication where resource contention is taken into consideration. The schedule representation scheme is flexible so that communication scheduling can be performed in a generic manner. Based on a general time formulation of the schedule performance, the algorithm improves an initial schedule in an efficient way. Experimental results show that significant improvement over existing methods can be obtained. Using the scheduling results, a parallel software video encoder was implemented and real-time performance was achieved.published_or_final_versio

Parallelization methodology for video coding - an implementation on the TMS320C80

This paper presents a parallelization methodology for video coding based on the philosophy of hiding as much communications by computation as possible. It models the task/data size, processor cache capacity, and communication contention, through a systematic decomposition and scheduling approach. With the aid of Petri-nets and task graphs for representation and analysis, it employs a triple buffering scheme to enable the functions of frame capture, management, and coding to be performed in parallel. The theoretical speedup analysis indicates that this method offers excellent communication hiding, resulting in system efficiency well above 90%. To prove its practicality, a H.261 video encoder has been implemented on a TMS320C80 system using the method. Its performance was measured, from which the speedup and efficiency figures were calculated. The only difference detected between the theoretical and measured data is the program control overhead that has not been accounted for in the theoretical model. Even with this, the measured speedup of the H.261 is 3.67 and 3.76 on four parallel processors (PPs) for QCIF and 352 × 240 video, respectively, which correspond to frame rate of 30.7 and 9.25 frames per second, and system efficiency of 91.8% and 94%, respectively. This method is particularly efficient for platforms with small number of parallel processors.published_or_final_versio

Adaptive parallel video-coding algorithm

Parallel encoding of video inevitably frame rate gives varying rate performance due to dynamically changing video content and motion field since the encoding process of each macro-block, especially motion estimation, is data dependent. A multiprocessor schedule optimized for a particular frame with certain macro-block encoding time may not be optimized towards another frame with different encoding time, which causes performance degradation to the parallelization. To tackle this problem, we propose a method based on a batch of near-optimal schedules generated at compile-time and a run-time mechanism to select the schedule giving the shortest predicted critical path length. This method has the advantage of being near-optimal using compile-time schedules while involving only run-time selection rather than re-scheduling. Implementation on the IBM SP2 multiprocessor system using 24 processors gives an average speedup of about 13.5 (frame rate of 38.5 frames per second) for a CIF sequence consisting of segments of 6 different scenes. This is equivalent to an average improvement of about 16.9% over the single schedule scheme with schedule adapted to each of the scenes. Using an open test sequence consisting of 8 video segments, the average improvement achieved is 13.2%, i.e. an average speedup of 13.3 (35.6 frames per second).published_or_final_versio

Distributed cooperative data transfer for UWB adhoc network

Published versio

Online placement of multi-component applications in edge computing environments

Mobile edge computing is a new cloud computing paradigm which makes use of small-sized edge-clouds to provide real-time services to users. These mobile edge-clouds (MECs) are located in close proximity to users, thus enabling users to seamlessly access applications running on MECs. Due to the coexistence of the core (centralized) cloud, users, and one or multiple layers of MECs, an important problem is to decide where (on which computational entity) to place different components of an application. This problem, known as the application or workload placement problem, is notoriously hard, and therefore, heuristic algorithms without performance guarantees are generally employed in common practice, which may unknowingly suffer from poor performance as compared to the optimal solution. In this paper, we address the application placement problem and focus on developing algorithms with provable performance bounds. We model the user application as an application graph and the physical computing system as a physical graph, with resource demands/availabilities annotated on these graphs. We first consider the placement of a linear application graph and propose an algorithm for finding its optimal solution. Using this result, we then generalize the formulation and obtain online approximation algorithms with polynomial-logarithmic (poly-log) competitive ratio for tree application graph placement.We jointly consider node and link assignment, and incorporate multiple types of computational resources at nodes