• Journal of Electrical Engineering and information Science
• /
• v.2 no.6
• /
• pp.74-81
• /
• 1997

Xcent-Net is a new system network designed to support a clustered SMP called SPAX(Scalable Parallel Architecture based on Xbar) that is being developed by ETRI. It is a duplicated hierarchical crossbar network to provide the connections among 16 clusters of 128 nodes. Xcent-Net is designed as a packet switched, virtual cut-through routed, point-to-point network. Variable length packets contain up to 64 bytes of data. The packets are transmitted via full duplexed, 32-bit wide channels using source synchronous transmission technique. Its plesiochronous clocking scheme eliminates the global clock distribution problem. Two level priority-based round-robin scheme is adopted to resolve the traffic congestion. Clear-to-send mechanism is used as a packet level flow control scheme. Most of functions are built in Xcent router, which is implemented as an ASIC. This paper describes the architecture and the functional features of Xcent-Net and discusses its implementation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39B no.2
• /
• pp.61-74
• /
• 2014

In recent years, development of femtocells are receiving considerable attention towards increasing the network coverage, capacity, and improvement in the quality of service for users. In 3GPP LTE-Advanced (LTE-A) system, to efficiently utilize the bandwidth, femtocell and macro cell uses the same frequency band, but this deployment poses a technical challenge of cross-tier interference to macro users. In this paper, the novel quality of service based fractional power control (QoS-FPC) scheme under the heterogeneous networks environment is proposed, which considers the users priority and QoS-requirements during the power allocation. The proposed QoS-FPC scheme has two focal points: firs, it protects the macrocell users uplink communication by limiting the cross-tier interference at eNB below a given threshold, and second, it ensures the optimization of femtocell users power allocation at each power adjustment phase. Performance gain is demonstrated with extensive system-level simulations to show that the proposed QoS-FPC scheme significantly decreases the cross-tier intereference and improves the overall users throughput.

• Journal of Digital Convergence
• /
• v.14 no.4
• /
• pp.79-88
• /
• 2016

The priority policy measures to draw peaceful unification is to induce North Kore to open the Internet. In order to induce the Internet open for exchange and cooperation in ICT industry of the two Koreas, a preparation task was drawn after analyzing ICT standard, current state of Internet and industry, and feasibility of North Korea. The priority task for the exchange and cooperation in ICT industry of North and South Korea requires an effort to develop North Korea's underdeveloped technology level. Thus, to decrease the technology gap must precede, providing state-of-the-art ICT infrastructure of the South. In this paper, the inducement to draw the Internet open of North Korea through technical specifications and standardization in ICT industry of the North and South was studied.

• The Journal of Korean Association of Computer Education
• /
• v.12 no.2
• /
• pp.13-22
• /
• 2009

In this paper, we propose a new dynamic syllabus composition system to solve the problems of a static syllabus which can appear in the field of computer education, where the relationship between pre-post study subjects is clear and teachers may grasp easily the degree of understanding of learners in real time. Our dynamic syllabus composition system is designed to be adjusted according to the physical change of the amount of education and the level of learners, which is based on the priority of educational objects. The result of instance performed on two groups of different entering behavior shows that the proposed method enhances the degree of transfer of education and helps us teach a class around the representative subject which has to be dealt with in the class, so that it is very effective for the achievement of educational objects prior to others.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.4
• /
• pp.159-167
• /
• 2015

We consider a wafer lot transfer/release planning problem from semiconductor wafer fabrication facilities to probing facilities with the objective of minimizing the deviation of workload and total tardiness of customers' orders. Due to the complexity of the considered problem, we propose a two-level hierarchical production planning method for the lot transfer problem between two parallel facilities to obtain an executable production plan and schedule. In the higher level, the solution for the reduced mathematical model with Lagrangian relaxation method can be regarded as a coarse good lot transfer/release plan with daily time bucket, and discrete-event simulation is performed to obtain detailed lot processing schedules at the machines with a priority-rule-based scheduling method and the lot transfer/release plan is evaluated in the lower level. To evaluate the performance of the suggested planning method, we provide computational tests on the problems obtained from a set of real data and additional test scenarios in which the several levels of variations are added in the customers' demands. Results of computational tests showed that the proposed lot transfer/planning architecture generates executable plans within acceptable computational time in the real factories and the total tardiness of orders can be reduced more effectively by using more sophisticated lot transfer methods, such as considering the due date and ready times of lots associated the same order with the mathematical formulation. The proposed method may be implemented for the problem of job assignment in back-end process such as the assignment of chips to be tested from assembly facilities to final test facilities. Also, the proposed method can be improved by considering the sequence dependent setup in the probing facilities.

• The Journal of Korea Robotics Society
• /
• v.3 no.3
• /
• pp.186-193
• /
• 2008

We propose a novel real-time obstacle avoidance method for rescue robots. This method, named the ELA(Emergency Level Around), permits the detection of unknown obstacles and avoids collisions while simultaneously steering the mobile robot toward safe position. In the ELA, we consider two sensor modules, PSD(Position Sensitive Detector) infrared sensors taking charge of obstacle detection in short distance and LMS(Laser Measurement System) in long distance respectively. Hence if a robot recognizes an obstacle ahead by PSD infrared sensors first, and judges impossibility to overcome the obstacle based on driving mode decision process, the order of priority is transferred to LMS which collects data of radial distance centered on the robot to avoid the confronted obstacle. After gathering radial information, the ELA algorithm estimates emergency level around a robot and generates a polar histogram based on the emergency level to judge where the optimal free space is. Finally, steering angle is determined to guarantee rotation to randomly direction as well as robot width for safe avoidance. Simulation results from wandering in closed local area which includes various obstacles and different conditions demonstrate the power of the ELA.

• Food Science and Preservation
• /
• v.11 no.2
• /
• pp.276-281
• /
• 2004

The study focused on setting priority among future core technologies that were derived by Delphi in agricultural management ＆ information using AHP. Items for the setting priority were decided as 'technology', 'market', and 'public concerns' by council. The future core technologies were divided as four parts by importance and R＆D level. Technologies that are consisted with upper two parts that have high importance were considered in the study. Questionnaires were given to 10 specialists in division of postharvest agriculture. As the results, 'market' was decided as a most important item. The most important technologies number were PⅠ16 in group Ⅰ, and PⅡ12 in group Ⅱ.

• The Journal of Engineering Research
• /
• v.3 no.1
• /
• pp.85-95
• /
• 1998

In this study, we consider a recursive procedure to obtain the stationary probability distribution for analyzing Coxian queueing networks with finite queues. This network deals with multiple class customers. Due to the state space representing multiple class customers, the sub-matrices corresponding to states can not be square matrices and can not be inverted. Therefore, we introduce more complex recursive method to avoid the singular problem. The open queueing network that we study consists of 3 parallel first-level sources linked to a single second level queue. We consider two types of schemes for entering a queue. The first scheme is assumed to be the first-blocked-first-enter (FBFE) and the second scheme is the higher-priority-first-enter (HPFE). Arrival and service times are assume to have a Coxian distribution with two phases. Comparison between the resulting using Gauss-Seidel method and recursive procedure will be shown.

• Journal of Electrical Engineering and information Science
• /
• v.2 no.3
• /
• pp.105-112
• /
• 1997

The performance of a shared memory multiprocessor system is very sensitive to process scheduling. w can enhance the performance of a whole system as well as of an individual process by taking the multiprocessor characteristics into account in the design of the process scheduler. In this paper, we proposed a general purpose scheduler for a shared memory multiprocessor, called the Two-Level Multi-Scan (TLMS) process scheduler, that considers the processor affinity loosely and decreases the interference among multiple processors greatly. The TLMS scheduler is composed of a local scheduler at each processor and a semi-global scheduler that balances the load among processors. In particular, the semi-global scheduler tries to minimize priority inversion, which is an important factor of the system performance. The TLMS scheduler also tries to reduce the number of resources to be shared and improves the processor utilization. to meet these requirements, th semi-global scheduler interacts with the operation of the local scheduler when a need arises, thus the name is loose processor-affinity. We also show that the proposed scheduling technique can be extended for other types of resources making it a general purpose resource management queue.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.5
• /
• pp.657-665
• /
• 2019

The domestic railway parts and equipment manufacturing industry is mainly focused on SMEs, and the majority of them are suffering from profitability because they cannot build economies of scale. Besides, they have survived in the form of importing technology products from overseas advanced countries and delivering them to domestic railway operators rather than having in-house technology. Therefore it is necessary to study whether the problems of the current railway industry can be identified and improved and at the same time, whether the government's railway industry development policy is properly reflected. literature studies related to technology commercialization, and conduct surveys of AHP questionnaires on the experts of the manufacturing industry of SMEs, academics / research institutes of the railway industry. After that, the Level 3 activation method AHP analysis was additionally performed on the important factors of Level 2 that have the highest importance and priority in Level 1. As a result of the AHP analysis, 'Technical Connectivity' was the most important method in the technical factor, and SME experts and academic and research institute experts were highly evaluated for 'commercialization ability' Competence in terms of importance. As for external support factors, it was analyzed that SME experts "support for manpower development" was important, while the other two group experts research and development support was important. In this study, the priority of the government support and policy priorities are suggested according to the capabilities of the railway manufacturing SMEs before the future R&D support.