• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.339-350
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• 2003

In this paper, we propose a simultaneous multithreading (SMT) architecture that improves instruction throughput by exploiting instruction level parallelism (ILP) and thread level parallelism (TLP). The proposed architecture issues and completes instructions belonging to the same thread in exact program order. The issue and completion policy greatly reduces the design complexity and hardware cost of our architecture, compared with others that employ out-of-order issue and completion. On the other hand, when the instructions belong to different threads, the issue and completion orders for those instructions may not necessarily be identical to the fetch order. The processor issues instructions simultaneously from multiple threads to functional units by exploiting ILP and TLP, and by dynamic resource sharing. That parallel execution notably improves performance and resource utilization with minimal additional hardware cost over the conventional superscalar processors. This paper proposes an SMT architecture with grouping as well as one without grouping. Without grouping, all threads dynamically and flexibly share most resources. On the other hand, in the SMT architecture with grouping, in which resources and threads are divided into several groups for design simplification, resources are shared only among threads belonging to the same group as those resources. Simulation results show that our processors with four and eight threads improve performance by three or more times over the conventional superscalar processor with comparable execution resources and policies, and that reasonable grouping reduces the design complexity of SMT processors with little negative effect on performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.6
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• pp.59-70
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• 2004

SMT(Simultaneous Multi Threading) architecture uses TLP(Thread Level Parallelism) and increases processor throughput, such that issue slots can be filled with instructions from multiple independent threads. Having multiple ready threads reduces the probability that a functional unit is left idle, which increases processor efficiency. To utilize those advantages for the SMT processors, the issue unit must control the flow of instructions from different threads and not create conflicts among those instructions, which make the SMT issue logic extremely complex. Therefore, our SMT architecture, which is modeled in this paper, uses an in-order-issue and completion scheme, and therefore, can use a simple issue mechanism with a scoreboard already instead of using register renaming or a reorder buffer. However, an SMT scoreboarding mechanism is still more complex and costlier than that of a single threaded conventional processor. This paper proposes an optimal implementation of a scoreboarding mechanism for an ARM-based SMT architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.86-92
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• 2011

In this paper, we propose a novel hardware MPI(Message Passing Interface) unit which supports message passing in multiprocessor system which use distributed memory architecture. MPI Hardware unit processes data synchronization, transmission and completion, and it supports processor non-blocking operation so it reduces overhead according to synchronization. Additionally, MPI hardware unit combines ready entry, request entry, reserve entry which save and manage the synchronized messages and performs the multiple outstanding issue and out of order completion. According to BFM(Bus Functional Model) simulation result, the performance is increased by 25% on many to many communication. After we designed MPI unit using HDL, with synopsys design compiler we synthesized, and for synthesis library we used MagnaChip $0.18{\mu}m$. And then we making prototype chip. The proposed message transmission interface hardware shows high performance for its increase in size. Thus, as we consider low-cost design and scalability, MPI hardware unit is useful in increasing overall performance of embedded MPSoC(Multi-Processor System-on-Chip).

• International Journal of Control, Automation, and Systems
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• v.2 no.1
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• pp.76-82
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• 2004

A robust fuzzy controller is designed to stabilize a class of solvable nonlinear descriptor systems with time-varying delay. First, a new modeling and control method for nonlinear descriptor systems is presented with a fuzzy descriptor model. A sufficient condition for the existence of the fuzzy controller is given in terms of a series of LMIs. Then, a less conservative fuzzy controller design approach is obtained based on the fuzzy rules and weights. This method includes the interactions of the different subsystems into one matrix. The effectiveness of the presented approach and the design procedure of the fuzzy controller are illustrated by way of an example.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.800-809
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• 2007

Current payment methods have many faults which are detrimental to the formation and completion of a project. This includes the use of unfair payment terms, pricing strategies and payment mechanisms between the contracting parties. This resulted in being criticised and remain in doubt, the use of current payment methods to reward good contractors and to distinguish poorly performed construction firms. In order to have an insight into this issue, a structured survey was conducted amongst UK construction practitioners. It was found that traditional pricing methods (i.e. lump sum and unit price), payment methods (i.e. interim valuation) and retention still dominate current practice. The empirical findings show that there are significant differences in the use of pricing and payment methods (when making and receiving payments) in construction. Significant differences also found in the factors affecting the choice of pricing methods when making (and receiving) construction payments. The paper concludes with analysis of the findings and future direction of research in payment systems is also provided.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.369-376
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• 2018

The majority of construction projects, from the initiation phase to the project completion and operation phase, are influenced by various types of corruption. Iran, as a developing country, has been suffering from this issue in bidding, tendering procedure, contracts etc. Therefore, due to the importance of this issue, this study attempted to identify the causes of corruption and evaluate the most significant factors in the construction projects in Iran. To this aim, an intensive literature review was performed to investigate the various types of corruption and identify the potential factors causing corruption in construction projects. The questionnaire survey was designed, considering twelve forms of corruption, including 77 causes of corruption in construction projects in Iran. Out of 220 distributed questionnaires, 188 were returned by the participants. The valid collected data sets were analyzed and then Exploratory Factor Analysis was applied. It was discovered that "Inappropriate power-sharing," "Lack of obligation for human resources to properly use resources and abide by the rules and regulations" and "Lack of any monitoring of the government's performance" are the most significant factors. Findings from the study would be valuable for the construction projects authorities and academia in order to combat corruption in the construction projects.

• Korea Trade Review
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• v.44 no.6
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• pp.87-103
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• 2019

L/C(Letter of Credit) is a common payment term designed to prevent credit risk in international trade. However, most companies prefer T/T (Telegraphic Transfer) payment due to its time and cost efficiency. According to related statistics, more than 70% of international trade contracts are based on T/T rather than other payment terms. The time required from the export negotiation to the completion of the export transaction and collection in international trade is very long. In this process, disputes related to settlement are continuous, so caution should be exercised. Therefore, whether or not the export payment is recovered in a timely manner is the core issue of trade transactions for exporters. The purpose of this study is to identify problems that cause delayed payments during settlement by the remittance (T/T) method, which can lead to settlement risk, in order to investigate those factors which can lead to delays in payments and increased risk as well as to determine ways to prevent such factors in advance. According to empirical findings, trading experience, transaction duration, and contract contents can be important determinants in terms of payment delays. Industry uniqueness and market uncertainty were found to be in opposition to the hypothesized relationships. The results of this study will be useful for trading companies to reduce their payment risk.

• Korean System Dynamics Review
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• v.11 no.4
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• pp.25-59
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• 2010

The Korean government has operated various mega-development projects in order to help nation progress into the future. However, many problems and concerns have been raised on the mega-projects' delay and failure in South Korea. Moreover, there are many technical and executive problems; such as trial and error of development work, failure of validity test, complicated decision-making processes, and so on. With these concerns and problems to mega-development projects, finding a sustainable development from mega-projects is becoming a new issue in the field of mega-development projects. Therefore, the main purpose of this study is to investigate whether or not most mega-development projects conducted by the government exactly corresponds with sustainable development (such as environmental soundness, economic efficiency and social equity) focusing on Saemangeum project. Using causal loop analysis, this study gives some significant results to us. First, for environmental soundness, both central and local government should ensure water-purity control system for farming, industry, leisure, and others. Second, for economic efficiency, both governments not only have to secure a budget for completion of infrastructure of the Saemangeum project but also support financial assistance to Saemangeum project. Third, for social equity, three local governments (i.e., Gunsan, Gimje, and Buan) should stop debate and conflict with regard to an administrative district of Saemangeum region. Finally, most politicians should not use Saemangeum project for political means. Rather, they should recognize the project as a motive power for economic development of Jeollabukdo.

• Journal of Environmental Policy
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• v.1 no.1
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• pp.111-128
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• 2002

The Ministerial Declaration of the 4th WTO Ministerial Meeting at Doha in November 2001 announced the launch of the New Round and a completion date of January 1st, 2005. It agreed to eventually negotiate trade and environment linkage issues, such as the relationship between the WTO rules and Multilateral Environment Agreements and the reduction or elimination of tariff and non-tariff barriers to environmental goods and services. The Committee on Trade and Environment was instructed to pursue work on all items on its agenda within the current terms of reference and to give particular attention to the effects of environmental measures on market access, relevant provisions of the TRTPS Agreement, and labelling requirements for environmental purposes. This means that far the first time, the members of the WTO will discuss and negotiate trade and environment linkage in the framework of multilateral trade negotiation. Korea, from the standpoint of a smaller open economy heavily dependent on international trade, is obliged to overcome the challenges imposed by the environment agenda in the Doha declaration. This study examined the linkage among environment, economic growth and international trade in order to review the possible trade and environment policy implications in Korea. Mutual supportiveness of trade and environment depends much on the effectiveness of trade and environment policy coordination. In this regard, we conclude that the Korean government should provide an appropriate institutional framework to promote closer cooperation among policy makers engaged in negotiations. Trade and environment policy review and environmental impact assessment of trade negotiation should be considered as a work programme of this institutional policy coordination framework.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.265-281
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• 2017

For shallow tunnel constructions, settlement of the ground surface is a main issue. Recent technical developments in shield TBM tunneling technique have enabled a decrease in such settlements based on tunneling with ground deformation controls. For this objective, the tail void grouting is a common practice. Generally surface settlements in a soil of low permeability occur during a tunnel construction but also during a long period after completion of the tunnel. The long-term settlements occur mainly due to consolidation around the tunnel. The consolidation process is caused and determined by the tail void grouting which leads to an excess pore water pressure in the vicinity of the tunnel. Because of this, the grouting pressure has a strong effect on the long-term settlements in the shield tunneling. In order to investigate this effect, a series of coupled hydro-mechanical 3D finite element simulations have been performed. The results show that an increase in grouting pressure reduces the short-term settlements, but in many cases, it doesn't lead to a reduction of the final settlements after the completion of consolidation. Thereby, the existence of a critical grouting pressure is identified, at which the minimal settlements are expected.