• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1222-1223
• /
• 2007

This paper suggests a 6-pulse-shift converter with PWM current-source inverter based on buck-boost configuration to improve the efficiency and to reduce the switching frequency of inverter for photovoltaic generation system, the device can be operated as interface system between solar module system and power system grid without energy storage cell. the circuit has six current-source buck-boost converter which operate chopper part has one full bridge inverter which make a decision the polarity of AC output. Therefore, the proposed PWM power inverter has advantages such as the reduction of witching loss and realization of unity power factor operation. the theoretical backgrounds are discussed and the input-output characteristics for the implemented prototype inverter using TMS320F2812 are verified experimentally in this paper.

• Journal of Internet Computing and Services
• /
• v.4 no.5
• /
• pp.51-60
• /
• 2003

Asynchronous iteration is a way to reduce performance degradation of some parallel algorithms due to load imbalance or transmission delay between computing nodes, which requires asymmetric communication between the nodes of different speeds. To implement such asynchronous communication on distributed memory systems, we suggest an MPMD method that creates an additional separate server process on each computing node, and compare it with an SPMD method that creates a single process per node.

• Language and Information
• /
• v.2 no.1
• /
• pp.177-213
• /
• 1998

conflicting criterial used in identifying words have called the lexical integrity principle into question. That is, cases where the morphological word does not coincide with the syntactic word have notivated the syntactic view of word derivation, as pointed out by Bresnan and Mchombo(1995). Further, the implicit desire to make the clausal structure of Korean parallel to those posited for English(Chomsky 1991) and French(Pollock 1989) has also led most of the current literature on Korean morphology to claim that Korean verbal inflections head their own functional projections such as AgrP, TP, and MP im syntax. In this paper, I will first argue against such a syntactic view. After reviewing some basic properties of Korean verbal inflections, I will show that the evidence from mismatch phenomena supports the lexical integrity principle over the head-movement theories of word derivation. Then, I will propose a theory of lexical grammar which maintains the lexical integrity principle while retaining the effects of functional projections and syntactic movement.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.217-219
• /
• 2004

The installation of small sized dispersed generation(DG) units operating in parallel with the utility supply presents several technical problems for the protection and control of the system. One of the critical concerns is the occurrence of islanding. Hence, this paper propose the Digital Universal Relay(DUR) including anti-islanding function as DG interconnection interface. The existent islanding detection algorithms are examined. And the most effective and reliable method of those is modified for DUR application. The modified algorithm is evaluated through the modeling of the test system by PSCAD/EMTDC.

• Electronics and Telecommunications Trends
• /
• v.37 no.6
• /
• pp.43-53
• /
• 2022

Message Passing Interface (MPI) collective communication has been applied to various science and engineering area such as physics, chemistry, biology, and astronomy. The parallel computing performance of the data-intensive workload in the above research fields depends on the collective communication performance. To overcome this limitation, MPI collective communication technology has been extensively researched over the last several decades to improve communication performance. In this paper, we provide a comprehensive survey of the state-of-the-art research performed on the MPI collective communication and examine the trends of recently developed technologies. We also discuss future research directions for providing high performance and scalability to large-scale MPI applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.354-356
• /
• 2021

For science applications that requires rapid transfer and sharing of large volume data, many efforts to improve data transfer performance have been made based on concurrency, parallelism and pipelining in data transfer applications such as Globus/GridFTP. In this paper, as a similar trial, experiments have been conducted for the expected transfer throughput enhancement by the increased number of network interface and parallelism in the Mptcp emulation environment and the result is presented.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.2
• /
• pp.19-24
• /
• 2007

With recent advancement of high-speed, multi-gigabit data transmission capabilities, serial links have been more widely adopted in industry than parallel links. Since the parallel link design forces its transmitter to transmit both the data and the clock to the receiver at the same time, it leads to hardware's intricacy during high-speed data transmission, large power consumption, and high cost. Meanwhile, the serial links allows the transmitter to transmit data only with no synchronized clock information. For the purpose, clock and data recovery circuit becomes a very crucial key block. In this paper, a 5.4Gbps half-rate bang-bang CDR is designed for the applications of high-speed graphic DRAM interface. The CDR consists of a half-rate bang-bang phase detector, a current-mirror charge-pump, a 2nd-order loop filter, and a 4-stage differential ring-type VCO. The PD automatically retimes and demultiplexes the data, generating two 2.7Gb/s sequences. The proposed circuit is realized in 66㎚ CMOS process. With input pseudo-random bit sequences (PRBS) of $2^{13}-1$, the post-layout simulations show 10psRMS clock jitter and $40ps_{p-p}$ retimed data jitter characteristics, and also the power dissipation of 80mW from a single 1.8V supply.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.10
• /
• pp.31-38
• /
• 2008

This paper describes sensor network system implementation for the IEEE 1451.2 standard which guarantees compatibilities between various wired sensors. The proposed system consists of the Network Capable Application Processor(NCAP) in the IEEE 1451.0, the Transducer Independent Interface(TII) in the IEEE 1451.2, the Transducer Electronic Data Sheet(TEDS) and sensors. The research goal of this study is to minimize and optimize system complexity for IC design. The NCAP is implemented using C language in personal computer environment. TII is used in the parallel port between PC and an FPGA application board. Transducer is implemented using Verilog on the FPGA application board. We verified the proposed system architecture based on the standards.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.5B
• /
• pp.899-912
• /
• 2000

PVM provides users with a single image of high performance parallel computing machine by collecting machines distributed over a network. Low communication overhead is essential to effectively run applications on PVM based platforms. In the original PVM, three times of memory copies are required for a PVM task to send a message to a remote task, which results in performance degradation. We propose a zero-copy model using global shared memory that can be accessed by PVM tasks, PVM daemon, and network interface card(NIC). In the scheme, a task packs data into global shared memory, and notify daemon that the data is ready to be sent, then daemon routes the data to a remote task to which it is sent with no virtual data copy overhead. Experimental result reveals that the message round trip time between two machines is reduced significantly in the proposed zero-copy scheme.

• Atmosphere
• /
• v.15 no.1
• /
• pp.35-46
• /
• 2005

Today, the outreach of National Meteorological Service such as PC cluster based Numerical Weather Prediction (NWP) technique is vigorous in the world wide. In this regard, WMO (World Meteorological Organization) asked KMA (Korea Meteorological Administration) to formulate a regional project, which cover most of RA II members, using similar technical system with KMA's. In that sense, Meteorological Research Institute (METRI) in KMA developed Mongolian NWP System (MNWPS) based on PC cluster and transferred the technology to Weather Service Center in Mongolia. The hybrid parallel algorithm and channel bonding technique were adopted to cut cost and showed 41% faster performance than single MPI (Message Passing Interface) approach. The cluster technique of Beowulf type was also adopted for convenient management and saving resources. The Linux based free operating system provide very cost effective solution for operating multi-nodes. Additionally, the GNU software provide many tools, utilities and applications for construction and management of a cluster. A flash flood event happened in Mongolia (2 September 2003) was selected for test run, and MNWPS successfully simulated the event with initial and boundary condition from Global Data Assimilation and Prediction System (GDAPS) of KMA. Now, the cluster based NWP System in Mongolia has been operated for local prediction around the region and provided various auxiliary charts.