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KNLTER Network: Facilitating Global Data-Sharing

Taesang Huh, Sunil Ahn, Dukyun Nam, Hoe-Kyung Jung
2016 International Journal of Database Theory and Application  
Reliable data sharing and long-term data archiving and reuse are becoming very important in global cooperative research. Concomitantly, many types of global databased research have been conducted on the Long-Term Ecological Research (LTER) network, with the objective of getting it to respond effectively to future changes in ecology, environment, and climate, by monitoring long-term ecological and environmental data. Korean National Long-Term Ecological Research (KNLTER), however, lacks a system
more » ... for performing data collection, management, curation, and publication, and therefore global cooperative research through global data sharing is difficult in Korea. In this paper, we analyze one of the best practices link models, the TERN network, and the global data-sharing trend in the LTER area. Further, we propose a link model and necessary technologies for KNLTER and suggest a possible future direction for KNLTER. Therefore, two licenses can be used as a mapping format for global linking. Furthermore, DOI needs to be assigned to the datasets for data distribution. Although the data minting service by EZID can be used to receive IDs when the datasets are submitted, the DOI needs to be issued by a separate link to manage DOIs in the data center. Other necessary features include systematic data curation. In order for a data center to register as a member node of DataONE, the published data have to be accessible via long-term storage, each dataset has to be assigned an identifier, and resource maps and reliable data for data packages have to be provided. DOI A DOI is a unique identifier that can be issued to all objects, including internet documents and other digital content. It provides metadata such as authors and dates, and information on the location of the object so that users can have permanent access to the object. The International DOI Foundation (IDF) manages the policies and registrations in
doi:10.14257/ijdta.2016.9.9.22 fatcat:g2csfu2r6zdbphlomhc4zjr5oi

The hydrogen peroxide hypersensitivity of OxyR2 in Vibrio vulnificus depends on conformational constraints

Inseong Jo, Dukyun Kim, Ye-Ji Bang, Jinsook Ahn, Sang Ho Choi, Nam-Chul Ha
2017 Journal of Biological Chemistry  
Most Gram-negative bacteria respond to excessive levels of H 2 O 2 using the peroxide-sensing transcriptional regulator OxyR, which can induce the expression of antioxidant genes to restore normality. Vibrio vulnificus has two distinct OxyRs (OxyR1 and OxyR2), which are sensitive to different levels of H 2 O 2 and induce expression of two different peroxidases, Prx1 and Prx2. Although OxyR1 has both high sequence similarity and H 2 O 2 sensitivity comparable with that of other OxyR proteins,
more » ... R2 exhibits limited sequence similarity and is more sensitive to H 2 O 2 . To investigate the basis for this difference, we determined crystal structures and carried out biochemical analyses of OxyR2. The determined structure of OxyR2 revealed a flipped conformation of the peptide bond before Glu-204, a position occupied by glycine in other OxyR proteins. Activity assays showed that the sensitivity to H 2 O 2 was reduced to the level of other OxyR proteins by the E204G mutation. We solved the structure of the OxyR2-E204G mutant with the same packing environment. The structure of the mutant revealed a dual conformation of the peptide bond before Gly-204, indicating the structural flexibility of the region. This structural duality extended to the backbone atoms of Gly-204 and the imidazole ring of His-205, which interact with H 2 O 2 and invariant water molecules near the peroxidatic cysteine, respectively. Structural comparison suggests that Glu-204 in OxyR2 provides rigidity to the region that is important in H 2 O 2 sensing, compared with the E204G structure or other OxyR proteins.
doi:10.1074/jbc.m116.743765 pmid:28264933 pmcid:PMC5409488 fatcat:uwi4a2hx6jhojhul73jykeigcu

Reliability Assessment of Low-Power Processor Packages for Supercomputers
슈퍼컴퓨터에 사용되는 저전력 프로세서 패키지의 신뢰성 평가

Ju-Young Park, Daeil Kwon, Dukyun Nam
2016 Journal of the Microelectronics and Packaging Society  
While datacenter operation cost increases with electricity price rise, many researchers study low-power processor based supercomputers to reduce power consumption of datacenters. Reliability of low-power processors for supercomputers can be of concern since the reliability of many low-power processors are assessed based on mobile use conditions. This paper assessed the reliability of low-power processor packages based on supercomputer use conditions. Temperature cycling was determined as a
more » ... cal failure cause of low-power processor packages through literature surveys and failure mode, effect and criticality analysis. The package temperature was measured at multiple processor load conditions to examine the relationship between processor load and package temperature. A physics-of-failure reliability model associated with temperature cycling predicted the expected lifetime of low-power processors to be less than 3 years. Recommendations to improve the lifetime of low-power processors were presented based on the experimental results.
doi:10.6117/kmeps.2016.23.2.037 fatcat:whplfld4dfdjhdii6cs3kysd6q

Development of the Korean Spine Database and Automatic Surface Mesh Intersection Algorithm for Constructinge-Spine Simulator

Dongmin Seo, Hanmin Jung, Won-Kyung Sung, Dukyun Nam
2014 Journal of Applied Mathematics  
By 2026, Korea is expected to surpass the UN's definition of an aged society and reach the level of a superaged society. With an aging population come increased disorders involving the spine. To prevent unnecessary spinal surgery and support scientific diagnosis of spinal disease and systematic prediction of treatment outcomes, we have been developinge-Spine, which is a computer simulation model of the human spine. In this paper, we present the Korean spine database and automatic surface mesh
more » ... tersection algorithm to constructe-Spine. To date, the Korean spine database has collected spine data from 77 cadavers and 298 patients. The spine data consists of 2D images from CT, MRI, or X-ray, 3D shapes, geometry data, and property data. The volume and quality of the Korean spine database are now the world's highest ones. In addition, our triangular surface mesh intersection algorithm automatically remeshes the spine-implant intersection model to make it valid for finite element analysis (FEA). This makes it possible to run the FEA using the spine-implant mesh model without any manual effort. Our database and surface mesh intersection algorithm will offer great value and utility in the diagnosis, treatment, and rehabilitation of patients suffering from spinal diseases.
doi:10.1155/2014/471756 fatcat:nt6ne7wjmvhh7p2kovy2q34x7i

Energy efficient topology for wireless microsensor networks

Han Namgoong, Dongman Lee, Dukyun Nam
2005 Proceedings of the 2nd ACM international workshop on Performance evaluation of wireless ad hoc, sensor, and ubiquitous networks - PE-WASUN '05  
We analyze the relationship between energy consumption and topology in wireless microsensor networks. Energy consumption is the total energy required for a message to be delivered to a destination microsensor from a source microsensor. We first consider the factors in energy consumption -radio propagation models, the topology of microsensors, the probability of connectivity between microsensors and etc. The radio propagation model tells us how much energy the environment of message propagation
more » ... equires, and the topology is the logical configuration among microsensors. We analyze the energy consumption from two different aspects: the propagation model and the topology. A propagation model may consume more energy than that of another model at the same topology, or, different topologies may require different amounts of energy in the same propagation model. The result of analysis shows that the consumed energy is in proportion to the number of neighbors, i.e. when the topology has fewer neighboring microsensors, it consumes less energy even though it must experience more hops to the destination. We also prove that the same result can be applied to any of the radio propagation models -such as free space propagation, urban area, obstructed in building, and etc. From the two analyses in the propagation model and topology, we can conclude that when a message goes to the destination of multihop, the topology with fewer neighboring microsensors consumes less energy than that of more neighbors. We also perform a simple analysis on the connectivity among microsensors as one of the energy consumption factors. Microsensors are prone to be disconnected by microsensor failures, temporary broken links, going into sleep mode, and etc. The disconnection requires an alternative path to the destination and (or) retransmission of the same message to the next microssensor, which consumes additional energy.
doi:10.1145/1089803.1089963 dblp:conf/pe-wasun/NamgoongLN05 fatcat:3d3cv2oq45dgdjpftyxreqojga

EDISON Science Gateway: A Cyber-Environment for Domain-Neutral Scientific Computing

Hoon RYU, Jung-Lok YU, Duseok JIN, Jun-Hyung LEE, Dukyun NAM, Jongsuk LEE, Kumwon CHO, Hee-Jung BYUN, Okhwan BYEON
2014 IEICE transactions on information and systems  
We discuss a new high performance computing service (HPCS) platform that has been developed to provide domain-neutral computing service under the governmental support from "EDucation-research Integration through Simulation On the Net" (EDISON) project. With a first focus on technical features, we not only present in-depth explanations of the implementation details, but also describe the strengths of the EDISON platform against the successful gateway. To validate the performance and
more » ... tility of the platform, we provide benchmarking results for the resource virtualization framework, and prove the stability and promptness of the EDISON platform in processing simulation requests by analyzing several statistical datasets obtained from a three-month trial service in the initiative area of computational nanoelectronics. We firmly believe that this work provides a good opportunity for understanding the science gateway project ongoing for the first time in Republic of Korea, and that the technical details presented here can be served as an useful guideline for any potential designs of HPCS platforms.
doi:10.1587/transinf.e97.d.1953 fatcat:3orxzpxzkba35e4wojwj5onu7m

Parallelization and Performance Optimization of the Boyer-Moore Algorithm on GPU
Boyer-Moore 알고리즘을 위한 GPU상에서의 병렬 최적화

Yosang Jeong, Nhat-Phuong Tran, Myungho Lee, Dukyun Nam, Jik-Soo Kim, Soonwook Hwang
2015 KIISE Transactions on Computing Practices  
키워드: Boyer-Moore 알고리즘, 병렬화, 성능 최적화, 알고리즘 cascading, 멀티스레딩 Dukyun Nam) (Jik-Soo Kim) (Soonwook Hwang) 서는 Boyer-Moore 알고리즘 실행시 검색 대상 문자열 이 길어질수록 GPU 상에서 이들을 병렬처리하기 위한 매핑 오버헤드가 증가하는 문제 및 병렬 실행에 참여하  ... 
doi:10.5626/ktcp.2015.21.2.138 fatcat:juy7lg352bfa3jspflfnru7hqy

Using the On-Package Memory of Manycore Processor for Improving Performance of MPI Intra-Node Communication
MPI 노드 내 통신 성능 향상을 위한 매니코어 프로세서의 온-패키지 메모리 활용

Joong-Yeon Cho, Hyun-Wook Jin, Dukyun Nam
2017 Journal of KIISE  
요 약 고성능 컴퓨팅 환경을 위해서 최근 등장한 차세대 매니코어 프로세서는 전통적인 구조의 메모 리와 함께 고대역 온-패키지 메모리를 장착하고 있다. Intel Xeon Phi Knights Landing(KNL) 프로세서 의 온-패키지 메모리인 Multi-Channel DRAM(MCDRAM)은 기존의 DDR4 메모리보다 이론적으로 네 배 높은 대역폭을 제공한다. 본 논문에서는 MCDRAM을 이용하여 MPI 노드 내 통신 성능을 향상시키기 위한 방안을 제안한다. 실험 결과, 제안된 기법을 사용할 경우 DDR4를 사용하는 경우와 비교해서 MPI 노드 내 통신 성능을 최대 272% 향상시킬 수 있음을 보인다. 또한 MCDRAM 활용 방법에 따른 성능 영 향뿐만 아니라 프로세스의 코어 친화도에 따른 성능 영향을 보인다. 키워드: Knights Landing, 온-패키지 메모리, MPI, 노드 내 통신, 고성능 컴퓨팅 Abstract The emerging next-generation
more » ... nycore processors for high-performance computing are equipped with a high-bandwidth on-package memory along with the traditional host memory. The Multi-Channel DRAM (MCDRAM), for example, is the on-package memory of the Intel Xeon Phi Knights Landing (KNL) processor, and theoretically provides a four-times-higher bandwidth than the conventional DDR4 memory. In this paper, we suggest a mechanism to exploit MCDRAM for improving the performance of MPI intra-node communication. The experiment results show that the MPI intra-node communication performance can be improved by up to 272 % compared with the case where the DDR4 is utilized. Moreover, we analyze not only the performance impact of different MCDRAM-utilization mechanisms, but also that of core affinity for processes.
doi:10.5626/jok.2017.44.2.124 fatcat:72vkuli34beubnxah27jn3p37e

OxyR2 Functions as a Three-state Redox Switch to Tightly Regulate Production of Prx2, a Peroxiredoxin ofVibrio vulnificus

Ye-Ji Bang, Zee-Won Lee, Dukyun Kim, Inseong Jo, Nam-Chul Ha, Sang Ho Choi
2016 Journal of Biological Chemistry  
The bacterial transcriptional regulator OxyR is known to function as a two-state redox switch. OxyR senses cellular levels of H 2 O 2 via a "sensing cysteine" that switches from the reduced to a disulfide state upon H 2 O 2 exposure, inducing the expression of antioxidant genes. The reduced and disulfide states of OxyR, respectively, bind to extended and compact regions of DNA, where the reduced state blocks and the oxidized state allows transcription and further induces target gene expression
more » ... y interacting with RNA polymerase. Vibrio vulnificus OxyR2 senses H 2 O 2 with high sensitivity and induces the gene encoding the antioxidant Prx2. In this study, we used mass spectrometry to identify a third redox state of OxyR2, in which the sensing cysteine was overoxidized to S-sulfonated cysteine (Cys-SO 3 H) by high H 2 O 2 in vitro and in vivo, where the modification deterred the transcription of prx2. The DNA binding preferences of OxyR2 5CA -C206D, which mimics overoxidized OxyR2, suggested that overoxidized OxyR2 binds to the extended DNA site, masking the ؊35 region of the prx2 promoter. These combined results demonstrate that OxyR2 functions as a three-state redox switch to tightly regulate the expression of prx2, preventing futile production of Prx2 in cells exposed to high levels of H 2 O 2 sufficient to inactivate Prx2. We further provide evidence that another OxyR homolog, OxyR1, displays similar three-state behavior, inviting further exploration of this phenomenon as a potentially general regulatory mechanism. Downloaded from FIGURE 3. Expression levels of prx2 in response to various levels of H 2 O 2 and a working model for OxyR2 as a three-state redox switch. A, wild-type V. vulnificus was grown anaerobically to an A 600 of 0.3 and exposed to various concentrations of H 2 O 2 as indicated for 3 min. Total RNAs were isolated, and the relative levels of prx2 (black bars) and oxyR2 (gray bars) transcripts were determined by quantitative real-time PCR analyses. The level of each transcript from wild type unexposed to H 2 O 2 is presented as 1. *, statistically significant difference (p Ͻ 0.05) between groups. B, transcriptional activity of OxyR2-C206D. Cultures were grown aerobically to an A 600 of 0.5, total RNAs were isolated, and the relative levels of prx2 transcript were determined by quantitative real-time PCR analyses. The level of transcript from negative control (NC) is presented as 1. Negative control was OH0703 (pJH0311). OxyR2, OH0703 (pDY1025); OxyR2-C206D, OH0703 (pBANG1416). All data in A and B represent mean Ϯ S.D. (error bars). C, OxyR2 shifts to three different redox states, revealing different transcriptional activities in response to various levels of H 2 O 2 in cells (solid line) as indicated. Concurrently, the prx2 expression (dotted line) varies, depending on the redox states of OxyR2. C 206 -SO 2/3 H, overoxidized Cys 206 with Cys 206 -SO 2 H and/or Cys 206 -SO 3 H.
doi:10.1074/jbc.m115.710343 pmid:27268058 pmcid:PMC4965554 fatcat:rbqndqc46nhatlt3ffkjmnzdou

Design of Web based Simulation Provenance Data Sharing Service
웹 기반 시뮬레이션 이력출처 데이터 공유 서비스 설계

Youngjin Jung, Dukyun Nam, Jinseung Yu, JongSuk Ruth Lee, Kumwon Cho
2014 The Journal of the Korean Institute of Information and Communication Engineering  
Web based simulation service is actively utilized to computably analyze various kinds of phenomena in real world according to progress of computing technology and spread of Network. However it is hard to share data and information among users on the services, because most of web based simulation services do not share and open simulation processing information and results. In this paper, we design a simulation provenance data sharing service on EDISON_CFD (EDucation-research Integration
more » ... n On the Net for Computational Fluid Dynamics) to share the calculated simulation performance information. To store and share the simulation processing information, we define the simulation processing step as "Problem → Plan, Design → Mesh → Simulation performance → Result → Report." Users can understand a problem solving method through a computer simulation by searching the simulation performance information with Search/Share API of the store. Besides, this opened simulation information can reduce the waste of calculation resource to process same simulation jobs. 키워드 : EDISON, 웹 기반 시뮬레이션 서비스, 이력출처, 데이터 공개, 워크플로우
doi:10.6109/jkiice.2014.18.5.1128 fatcat:2wldyicjenh3xkk3f7pfd7cjky

Optical TCAD on the Net: A tight-binding study of inter-band light transitions in self-assembled InAs/GaAs quantum dot photodetectors

Hoon Ryu, Dukyun Nam, Bu-Young Ahn, JongSuk Ruth Lee, Kumwon Cho, Sunhee Lee, Gerhard Klimeck, Mincheol Shin
2013 Mathematical and computer modelling  
A new capability of our well-known NEMO 3-D simulator (Ref. Klimeck et al., 2007 [10]) is introduced by carefully investigating the utility of III-V semiconductor quantum dots as infrared photodetectors at a wavelength of 1.2-1.5 µm. We not only present a detailed description of the simulation methodology coupled to the atomistic sp 3 d 5 s * tight-binding band model, but also validate the suggested methodology with a focus on a proof of principle on small GaAs quantum dots (QDs). Then, we move
more » ... the simulation scope to optical properties of realistically sized dome-shaped InAs/GaAs QDs that are grown by selfassembly and typically contain a few million atoms. Performing numerical experiments with a variation in QD size, we not only show that the strength of ground state interband light transitions can be optimized via QD size-engineering, but also find that the hole ground state wavefunction serves as a control factor of transition strengths. Finally, we briefly introduce the web-based cyber infrastructure that is developed as a governmentfunded project to support online education and research via TCAD simulations. This work not only serves as a useful guideline to experimentalists for potential device designs and other modelers for the self-development of optical TCAD, but also provides a good chance to learn about the science gateway project ongoing in the Republic of Korea.
doi:10.1016/j.mcm.2012.11.024 fatcat:z7l47qkybfaptgkfnoxahzth2i

Enhancing the Performance of Multiple Parallel Applications using Heterogeneous Memory on the Intel"s Next-Generation Many-core Processor
인텔 차세대 매니코어 프로세서에서의 다중 병렬 프로그램 성능 향상기법 연구

Seungwoo Rho, Seoyoung Kim, Dukyun Nam, Geunchul Park, Jik-Soo Kim
2017 Journal of KIISE  
Nam) (Geunchul Park) (Jik-Soo Kim) 그림 1 KNL 구조 개요 Fig. 1 KNL Architecture Overview 1.  ...  Applications using Heterogeneous Memory on the Intel's Next-Generation Many-core Processor) 노 승 우 † 김 서 영 † 남 덕 윤 † † 박 근 철 † † 김 직 수 † † † (Seungwoo Rho) (Seoyoung Kim) (Dukyun  ... 
doi:10.5626/jok.2017.44.9.878 fatcat:6fkqpdh6knbblmqvprcvh2tkea

Transcriptomic Identification and Biochemical Characterization of HmpA, a Nitric Oxide Dioxygenase, Essential for Pathogenesis of Vibrio vulnificus

Dukyun Kim, Eun Jung Na, Suhyeon Kim, Jung Sung Kim, Young Hyun Jung, Jiafu Cao, Ho Jae Han, Iel Soo Bang, Jin-Wook Yoo, Nam-Chul Ha, Sang Ho Choi
2019 Frontiers in Microbiology  
Nitric oxide (NO) and its derivatives are important effectors of host innate immunity, disrupting cellular function of infecting pathogens. Transcriptome analysis of Vibrio vulnificus, an opportunistic human pathogen, identified a set of genes induced upon exposure to NO. Among them, VvhmpA (V. vulnificus hmpA), encoding a multidomain NO dioxygenase, was the most greatly induced upon exposure to NO and was thus further characterized. Absorption spectra demonstrated that VvHmpA is a heme protein
more » ... in which the heme iron can exist in either reduced, NO-bound, or oxidized state. Biochemical studies revealed that VvHmpA is a flavohemoglobin containing equimolar amounts of heme and FAD as cofactors. The K M and k cat values of VvHmpA for NO at 37°C, the temperature encountered by V. vulnificus in the host, were greater than those at 30°C, indicating that VvHmpA detoxifies high levels of NO effectively during infection. Compared with the wild type, the VvhmpA mutant exhibited a lower NO-decomposition activity and impaired growth in the presence of NO in vitro. Also, the cytotoxicity and survival of the VvhmpA mutant infecting the NO-producing murine macrophage cells were lower than those of the wild type. Furthermore, the mouse lethality of the VvhmpA mutant was reduced compared to that of the parental wild type. The combined results revealed that VvHmpA is a potent virulence factor that is induced upon exposure to NO and important for the survival and pathogenesis of V. vulnificus during infection.
doi:10.3389/fmicb.2019.02208 pmid:31616401 pmcid:PMC6768983 fatcat:zf3cr2dxsvgpdoc5rn25rxdtam

Scalable group membership service for mobile Internet

Bumho Kim, Dongman Lee, Dukyun Nam
Proceedings of the Seventh IEEE International Workshop on Object-Oriented Real-Time Dependable Systems. (WORDS 2002)  
Group communication system (GCS) is a useful mechanism for constructing reliable, fault-tolerant distributed application. When GCS is extended in mobile environment, the membership change occurs frequently due to the mobility of mobile nodes and unreliable wireless communication within a cell. In this paper, we propose a scalable group communication scheme to support mobile systems in an Internet environment with wireless cells. Our scheme leverages the layered approach, our previous work, to
more » ... hance the scalability. Furthermore, to shield group view from the mobility and temporary disconnection of mobile hosts, we extend the hierarchical view management of layered approach. The simulation result shows that our scheme can reduce the overhead of membership management and the number of messages exchanged to complete the view event process.
doi:10.1109/words.2002.1000065 dblp:conf/words/KimLN02 fatcat:3piny4wbkbctbmivr26676ajxu

The implementation and analysis of OCI-based group communication support in CORBA

Dongman Lee, Dukyun Nam, Hee Yong Youn, Chansu Yu
Proceedings 2001 Pacific Rim International Symposium on Dependable Computing  
Object replication is a technique to enhance fault tolerance and high availability. Group communication is a useful mechanism guaranteeing the consistency among replicated objects. We propose a generic group communication framework that allows transparent plug-in of various group communication protocols with no modification of existing CORBA. For this, we extend the Open Communications Interface (OCI) to support interoperability, reusability of existing group communication, and independency on
more » ... RB and OS. The proposed scheme is composed of group membership component, group IOR component, and group multicast component. Experiment results show that group object invocations using the proposed scheme produce almost constant latency regardless of the number of members while the latency of multiple object invocations using IIOP constantly increases. object group needs to be maintained for constructing reliable and fault-tolerant distributed applications [14] . Group communication service (GCS) is a useful mechanism guaranteeing the consistency of the states of all the member objects. It maintains a view, a list of the currently active and connected members in an object group, and also informs the running objects of the updated view whenever it changes. The consistency can be guaranteed by reliable delivery of messages to the members in the current view. CORBA provides many attractive features like portability and interoperability that allow distributed objects to transparently interact with each other in heterogeneous and distributed environment. As such, a single group communication protocol would not satisfy all the needs of CORBA group applications. There have been several approaches for supporting group communication service in CORBA [2, 8, 10, 12, 13 ]. However, the approaches do not support transparent plug-in of group communication protocols into CORBA, and thus CORBA application programmers cannot directly exploit the protocols. Therefore, there must be a generic group communication framework that allows transparent plug-in of various group communication protocols via a standard CORBA interface. We propose a mechanism that allows such framework with no modification of existing CORBA. The proposed mechanism leverages the OCI (Open Communications Interface) [6] with Group Communication Inter-ORB Protocol (GCIOP) as a group communication instantiation of General Inter-ORB Protocol (GIOP) and assigns the CORBA object to each process member in the group communication protocol. Group name, ordering type, and state as attributes are added to the Info Object, and the interfaces of the OCI were extended to support group semantics. We implement the proposed scheme on top of our group communication protocol using an ORB supporting OCI. Experiment results show that group object invocation using the proposed scheme has almost fixed latency regardless of the number of members while the latency of multiple object invocations using IIOP constantly increases. The reminder of the paper is structured as follows. Section 2 discusses the existing approaches for group communication in CORBA. Section 3 explains internal procedures and implementation of each 3 component in the proposed scheme. And Section 4 analyses the performance of the extended OCI. Conclusion follows in Section 5. Related Work Group communication services for CORBA can be categorized into three approaches such as integration approach, service approach, and interception approach [3, 13] . Examples are Electra [8], Object Group Service [2, 3], Eternal [10], and respectively. Electra integrates group communication service with CORBA by extending Basic Object Adapter (BOA). The implementation and performance of the system are efficient since there is no intermediate object between ORB and group communication system. However, this approach needs to modify ORB for creating group reference and supporting group communication. Object Group Service (OGS) [2] provides a new CORBA Object Service for group communication. This approach is independent of ORB and guarantees portability with CORBA Object Service. However, it cannot utilize existing group communication systems and has potential drawback on the performance. Eternal [10] and Eternal interceptor [14] capture and transmit Internet Inter-ORB Protocol (IIOP) messages to the replication manager, which maps the messages onto the group communication system. This approach need not modify ORB as in the case of using interceptor. However, it is dependent on the OS since interceptor is implemented in the system call level. Open Communications Interface (OCI) [6] provides plug-in protocol interfaces for CORBA. It implements the Acceptor/Connector module [18] in ORB. The module distinguishes connection establishment from service initialization occurring in the communication of a client/server model. The interfaces are Buffer, Acceptor, Transport, Connector, Connector Factory, Registries, and Info objects [15]. A Buffer holds data in an array of octets and maintains a position counter, which are used in communications between client and server. Info objects provide information on Acceptor, Transport, Connector, and Connector Factory. Figure 1 shows how OCI incorporates a given transport protocol with
doi:10.1109/prdc.2001.992709 dblp:conf/prdc/LeeNYY01 fatcat:qn5fdxrzfncsvai5hvjio67pbu