• Journal of Computing Science and Engineering
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• v.5 no.2
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• pp.121-130
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• 2011

Recent research indicates that transient errors will increasingly become a critical concern in microprocessor design. As embedded processors are widely used in reliability-critical or noisy environments, it is necessary to develop cost-effective fault-tolerant techniques to protect processors against transient errors. The register file is one of the critical components that can significantly affect microprocessor system reliability, since registers are typically accessed very frequently, and transient errors in registers can be easily propagated to functional units or the memory system, leading to silent data error (SDC) or system crash. This paper focuses on investigating the impact of register file soft errors on system reliability and developing cost-effective techniques to improve the register file immunity to soft errors. This paper proposes the register vulnerability factor (RVF) concept to characterize the probability that register transient errors can escape the register file and thus potentially affect system reliability. We propose an approach to compute the RVF based on register access patterns. In this paper, we also propose two compiler-directed techniques and a hybrid approach to improve register file reliability cost-effectively by lowering the RVF value. Our experiments indicate that on average, RVF can be reduced to 9.1% and 9.5% by the hyperblock-based instruction re-scheduling and the reliability-oriented register assignment respectively, which can potentially lower the reliability cost significantly, without sacrificing the register value integrity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1058-1067
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• 2004

Java virtual machine provides code compactness, simple execution engines, and platform-independence which are important features for small devices such as mobile or embedded device, but it has a big problem, such as low throughput due to stack-oriented operation. In this paper hardware lava accelerator targeted for mobile or embedded application is designed to eliminate the slow speed problem of lava virtual machine. The designed lava accelerator can execute 81 instructions of Java virtual machine(JVM)'s opcodes and be used as Java coprocessor of conventional 32-bit RISC processor with efficient coprocessor interface and instruction buffer. It consists of about 14,300 gates and its maximum operating frequency is about 50 Mhz under 0.35um CMOS technology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.259-265
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• 2014

When the trace-driven simulation is used for the performance analysis of widely used multicore processors in the initial design stage, much time and disk space is necessary. In this paper, statistical simulations are performed for a high performance multicore processor with various hardware configurations. For the experiment, SPEC2000 benchmarks programs are used for profiling and synthesizing new instruction traces. As a result, the performance obtained by our statistical simulation is comparable to that of the trace-driven simulation with the benefit of tremendous reduction in the simulation time.

• Journal of The Korean Association of Information Education
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• v.20 no.1
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• pp.1-12
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• 2016

The purpose of this study is to investigate and analyze the elementary teachers' use of smart-phone applications (apps) in teaching-learning activities. The range of study includes the current usage patterns of apps in teaching-learning activities, elementary school teachers' understanding about apps usage in their classroom and providing the guideline about how to use apps for each subject in the classroom. We surveyed 100 elementary school teachers who are interested in smart education in Seoul. These teachers have an experience of working in a smart research school or have a computer-related master's degree. We expect that the result of the study will helpful for the elementary school teachers to design teaching materials using apps.

• Journal of the Korean Institute of Navigation
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• v.23 no.2
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• pp.1-9
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• 1999

A trailer truck is a major equipment for transporting containers, and its driving is difficult due to two degrees of freedom which exist in the joint part between truck and trailer. Especially Backing a trailer truck to a parking home is a difficult exercise for all but the most skilled truck drivers. Normal driving instincts lead to erroneous movements. When watching a truck driver backing toward a parking home, one often observes the driver backing, going forward, backing again, going forward, etc., and finally backing to the desired position along the parking home. This paper discusses the design of the controller to control the steering of a trailer truck while only backing up to a parking home from an initial position. In this paper, we propose a backing up control system for a container trailer truck using fuzzy theory where the primitive fuzzy control rules are macroscopically designed using an expert's knowledge, and the control rules are regulated by LIBL(Linguistic Instruction Based Learning) to enable to back up successfully the trailer tuck to a parking home from arbitrary initial position. The validity of the proposed parking control system is shown by applying it to some initial positions on the simulator for container trailer truck.

• The Journal of Korean Association of Computer Education
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• v.7 no.2
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• pp.57-65
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• 2004

For the purpose of an effective instruction-learning process by systematic management of knowledge between instructor and learner in e-Learning, we have developed the authoring system in which the instructor is able to author easily on various lecture frames according to the instructional design theory. The authored contents with the relations among the learning objects based on SCORM standard would help learner to conceptualize the contents. A knowledge map is constructed on the relations among the learning objects using RDF of the semantic web. We introduce the ontology in which the instructor can make a dictionary of terminology by registering the words of the teaching area. The learning activity and comprehension of students can be assessed using each student's learning map along the interaction points which are introduced to present the individual learning by considering each student's capacity of understanding and achievement.

• Progress in Superconductivity and Cryogenics
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• v.7 no.1
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• pp.9-12
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• 2005

We have constructed an RSFQ 4-bit Arithmetic Logic Unit (ALU) in a pipelined structure. An ALU is a core element of a computer processor that performs arithmetic and logic operation on the operands in computer instruction words. We have simulated the circuit by using Josephson circuit simulation tools. We used simulation tools of XIC, $WRspice^{TM}$, and Julia. To make the circuit work faster, we used a forward clocking scheme. This required a careful design of timing between clock and data pulses in ALU. The RSFQ 1-bit block of ALU used in constructing the 4-bit ALU was consisted of three DC current driven SFQ switches and a half-adder. By commutating output ports of the half adder, we could produce AND, OR, XOR, or ADD functions. The circuit size of the 4-bit ALU when fabricated was 3 mm x 1.5 mm, fitting in a 5 mm x 5mm chip. The fabricated 4-bit ALU operated correctly at 5 GHz clock frequency. The chip was tested at the liquid-helium temperature.

• Journal of The Korean Association For Science Education
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• v.15 no.4
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• pp.394-403
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• 1995

The purpose of this study was to find out and analyze the science teacher's teaching methods. A total of 35 teaching methods were abstracted from the previous studies and the relating literatures. An instrument to measure the frequencies of using methods was developed and then tested to middle school science teachers. The Results of two factor analysis methods were compared. The results are as follows: The instruments's reliablity coefficient(Cronbach ${\alpha}$) was 0.7707. The teaching methods which middle school science teachers have used frequently were represented as the proposing of the learning objectives, the deductive teaching, the experimental activities by teacher's guide, the summarization after explanation, the reading text etc. Also, it was revealed that they have not use the diagnostic evaluation, the formative evaluation, the experimental activities by student's design, the instructional medium. By confirmatory factor analysis, the 1st factor included 13 teaching methods and 2nd and 3rd factor included 9 and 7 methods respectedly. The meaning of 1st factor was interpreted to stimulate student's learning motives. And the other's were about the development of instruction. In exploratory factor analysis factors were overlapped or more fined. These were due to the structure of factors.

• Journal of The Korean Association For Science Education
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• v.23 no.4
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• pp.341-359
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• 2003

The purpose of this research was to determine whether the present Korean teacher education programs for secondary science teachers are effective in improving the teacher conceptions of constructivism and STS. It is because the current Korean National Science Curriculum is consistent with both ideas as reforms. The teacher education programs sampled in the research included pre-service programs and two types of in-service programs. These two were the Qualifying In-service Program and the Iowa Korean Science Teachers Workshop. The Iowa Program was considered as an experimental program emphasized the constructivist perspective. Specially designed questionnaires for identifying teacher conceptions before and after the programs were administered. The conceptions about constructivism and STS improved as a result of the instruction in both of the pre-service and in-service teacher education programs. The pre-service program was more effective than the in-service programs in improving the teacher conceptions of both constructivism and STS. The Qualifying Inservice program was less effective than Iowa Korean Science Teachers Workshop. It was necessary for inservice programs for Korean secondary science teachers to be more emphasized on constructivism and STS. Iowa Korean Science Teachers Workshop provided a possible example to design a new special in-service program focused on constructivist perspectives as a way of aligning the Korean National Science Curriculum more quickly with recommended teaching practices in Korean schools.

• The Journal of Korean Association of Computer Education
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• v.4 no.2
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• pp.115-123
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• 2001

In the early stage of Web-based Instruction, it didn't gain preference in spite of it's benefit of convenience. The main reason is, I think, the lack of generality at the education system which eventually results in unsatisfactory facilities compared with the requirement of teachers and students. And the early systems don't make good use of the plenty data in distributed environment, and don't show so good reliablity due to lack of systematic design and development. In this paper, we suggest WBI developing technology using the concept of WBSE. WBI developing is consist of component of pre-developed education software, integration of component using its reusability, and production of more requirement-satisfactory education software.