Athanasia: A User-Transparent and Fault-Tolerant System for Parallel Applications

Hyungsoo Jung,Hyuck Han,Yeom, H. Y.,Sooyong Kang IEEE 2011 IEEE transactions on parallel and distributed syst Vol.22 No.10

<P>This article presents Athanasia, a user-transparent and fault-tolerant system, for parallel applications running on large-scale cluster systems. Cluster systems have been regarded as a de facto standard to achieve multitera-flop computing power. These cluster systems, as we know, have an inherent failure factor that can cause computation failure. The reliability issue in parallel computing systems, therefore, has been studied for a relatively long time in the literature, and we have seen many theoretical promises arise from the extensive research. However, despite the rigorous studies, practical and easily deployable fault-tolerant systems have not been successfully adopted commercially. Athanasia is a user-transparent checkpointing system for a fault-tolerant Message Passing Interface (MPI) implementation that is primarily based on the sync-and-stop protocol. Athanasia supports three critical functionalities that are necessary for fault tolerance: a light-weight failure detection mechanism, dynamic process management that includes process migration, and a consistent checkpoint and recovery mechanism. The main features of Athanasia are that it does not require any modifications to the application code and that it preserves many of the high performance characteristics of high-speed networks. Experimental results show that Athanasia can be a good candidate for practically deployable fault-tolerant systems in very-large and high-performance clusters and that its protocol can be applied to a variety of parallel communication libraries easily.</P>

National Information Resources Distribution System for Citizen Centric e-Government

Hyungsoo Jung,Heesop Kim(김희섭) 한국지역정보화학회 2002 한국지역정보화학회 학술발표대회 논문집 Vol.- No.-

TCP-GT: A New Approach to Congestion Control Based on Goodput and Throughput

Hyungsoo Jung,Shin-Gyu Kim,염헌영,강수용 한국통신학회 2010 Journal of communications and networks Vol.12 No.5

A plethora of transmission control protocol (TCP) congestion control algorithms have been devoted to achieving the ultimate goal of high link utilization and fair bandwidth sharing in high bandwidth-delay product (HBDP) networks. We present a new insight into the TCP congestion control problem; in particular an end-to-end delay-based approach for an HBDP network. Our main focus is to design an end-to-end mechanism that can achieve the goal without the assistance of any network feedback. Without a router’s aid in notifying the network load factor of a bottleneck link, we utilize goodput and throughput values in order to estimate the load factor. The obtained load factor affects the congestion window adjustment. The new protocol, which is called TCP-goodput and throughput (GT), adopts the carefully designed inversely-proportional increase multiplicative decrease window control policy. Our protocol is stable and efficient regardless of the link capacity, the number of flows, and the round-trip delay. Simulation results show that TCP-GT achieves high utilization,good fairness, small standing queue size, and no packet loss in an HBDP environment.

CPS: Operating System Architecture for Efficient Network Resource Management with Control-Theoretic Packet Scheduler

Hyungsoo Jung,한혁,염헌영,강수용 한국통신학회 2010 Journal of communications and networks Vol.12 No.3

The efficient network resource management is one of the important topics in a real-time system. In this paper, we present a practical network resource management framework, controltheoretic packet scheduler (CPS) system. Using our framework, an operating system can schedule both input and output streams accurately and efficiently. Our framework adopts very portable feedback control theory for efficiency and accuracy. The CPS system is able to operate independent of the internal network protocol state,and it is designed to schedule packet streams in fine-grained time intervals to meet the resource requirement. This approach simplifies the design of the CPS system, and leads us to obtain the intended output bandwidth. We implemented our prototype system in Linux, and measured the performance of the network resource management system under various network QoS constraints. The distinctive features of our principles are as follows: It is robust and accurate, and its operation is independent of internal network protocols.

Large-Memory Data Processing on a Remote Memory System using Commodity Hardware

정형수(Hyungsoo Jung),한혁(Hyuck Han),염헌영(Heon Y. Yeom) 한국정보과학회 2007 정보과학회논문지 : 시스템 및 이론 Vol.34 No.9

본 논문에서는 대용량 메모리 데이타 처리를 위한 범용 하드웨어 기반의 원격 메모리 시스템을 제안한다. 느린 디스크와 상대적으로 대단히 빠른 접근 속도를 보장하는 메모리 사이에 존재하게 되는 새로운 메모리 계층을 구현하기 위해, 본 논문에서는 다수의 일반적인 범용 데스크탑 PC들과 원격 직접 메모리 접근 (이하 RDMA) 기능이 가능한 고속 네트워크를 최대한 활용하였다. 제안된 새로운 계층의 메모리는 합리적인 응답시간과 용량을 제공함으로서 비교적 적은 양의 성능 부담으로서 대용량의 메모리 상주 데이타베이스를 구동할 수 있게 되었다. 제안된 원격 메모리 시스템은 원격 메모리 페이지들을 관리하게 되는 원격 메모리 시스템과, 원격 메모리 페이지의 교체를 관리하게 되는 원격 메모리 페이저로 구성되어 있다. 범용으로 쓰이는 MySQL과 같은 데이타베이스를 이용한 TPC-C 실험 결과로 볼 때 제안된 원격 메모리 시스템은 일반적인 대용량 메모리 데이타 처리 시스템에서 요구하는 다양한 요구조건을 만족시킬 수 있을 것이라 생각된다. This article presents a novel infrastructure for large-memory database processing using commodity hardware with operating system support. We exploit inexpensive PCs and a high-speed network capable of Remote Direct Memory Access (RDMA) operations to build a new memory hierarchy between fast volatile memory and slow disk storage. The new memory hierarchy guarantees a reasonable response time, and its storage size enables us to run large-memory database systems with little performance degradation. The proposed architecture has two main components: (1) a remote memory system inside the Linux kernel to manage other computers' memory pages efficiently and (2) a remote memory pager responsible for manipulating remote read/write operations on remote memory pages. We insist that the proposed architecture is practical enough to support the rigorous demands of commercial in-memory database systems by demonstrating the performance of publicly available main-memory databases (e.g., MySQL) on our prototyped system. The experimental results show very interesting results from the TPC-C benchmark.

결함내성 원격 메모리 시스템에 관한 연구

정형수 ( Hyungsoo Jung ),한혁 ( Hyuck Han ),김신규 ( Shin Gyu Kim ),염헌영 ( Heon Y. Yeom ) 한국정보처리학회 2007 한국정보처리학회 학술대회논문집 Vol.14 No.2

본 연구에서는 대용량 메모리 데이터 처리를 위한 범용 하드웨어 기반의 결함내성 원격 메모리 시스템의 성능을 분석하고자 한다. 대단히 빠른 접근 속도를 보장하는 휘발성 메모리를 이용한 원격 메모리 시스템의 실용적인 활용을 위해서는 결함내성의 성질이 필수적으로 보장되어야 한다. 본 연구에서는 RAID 기법과 유사한 방법을 이용하여 결함내성 메모리 시스템을 구현하고, 제안한 새로운 계층의 결함내성 메모리의 성능을 평가하고자 한다. 범용으로 쓰이는 MySQL과 같은 데이터베이스를 이용한 TPC-C 실험 결과로 볼 때 본 연구에서 구현한 결함내성 원격 메모리 시스템은 일반적인 대용량 메모리 데이터 처리 시스템에서 요구하는 필수요건인 결함내성 성질을 성공적으로 만족하고 있는 것으로 생각된다.

과학경진대회 참가 학생의 경험에 대한 질적 연구

정형수(Jung, Hyungsoo),양정호(Yang, Jungho) 학습자중심교과교육학회 2019 학습자중심교과교육연구 Vol.19 No.16

본 연구는 과학경진대회에 참가하였던 중학생 5명을 대상으로 2019년 1월부터 약3개월간 심층면담을 실시하여 그들이 대회 참가 과정에서 어떤 경험을 하였는지, 그리고 그 경험의 의미는 무엇인지를 살펴보았다. 주요 연구 결과를 살펴보면, 연구 참여자들은 성취에 대한 기대와 선택 받은 아이라는 자부심 속에서 지도교사의 지도를 따라가는 입장 보다는 자신이 주도하여 대회에 참가하고자 하는 의지를 보였다. 그리고 이러한 의지는 지도교사와 팀원, 부모 등 이 평소와는 다른 새로운 존재의 의미를 형성하는 계기가 되었다. 또한 연구 참여자들은 대회 준비 과정에서 오직 과학경진대회에 참가해야만 할 수 있는 특별한 경험들을 하거나, 노력의 가치, 자신의 가치 및 과학의 흥미로움 등 새로운 가치를 발견 했고 이러한 경험들은 과학경진대회 참가에 대한 만족감을 심어 주었다. 이런 과정에서 과학경진대회는 연구 참여자들에게 고진감래의 시간, 나만의 과학수업 시간으로서의 의미를 형성하였고, 이를 바탕으로 대회준비 과정에서 학생의 주도권 존중, 과학경진대회 지도 방법에 대한 연구의 필요성, 과학교과수업에 대한 반 성의 필요성 등을 시사점으로 제시하였다. This research was employed in-depth interviews with five middle school students who had participated in the national scientific contest for about three months from January 2019 to study what they experienced in the course of the contest and what the meaning of the experiences was. The results of the study showed that the participants were willing to participate in the contest by their own initiative rather than following the instruction of the instructor in the expectation of achievement and self-esteem of the selected child. This willingness also led the instructor, team members and parents to form a new meaning that is different from usual. In addition, research participants found special values in the preparation of the contest, such as special experiences that only national scientific contest may have to attend, new values such as the value of effort, their own value and the interest of science, which gave them satisfaction with their participation in the contest. In this process, the national scientific contest formed a meaning for the research participants as a time for ‘sweet after bitter’ and a time for their own science class, and based on this suggestion, it presented the students respect for their initiative in the preparation of the contest, the need for research on how to instruct the national scientific contest, and the need to reflect on the science class.

RPA 툴과 Diaogflow를 활용한 Chatbot 서비스 개발

정순익(Sunik Jung),정제현(Jehyun Jung),박건우(Gunwoo Park),김형수(Hyungsoo Kim),고석주(Seokju Go) 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6

인공지능 기반 기술이 발전하면서 챗봇에 대한 수요가 급격히 늘어났다. 뿐만 아니라, 사무적인 업무까지 로봇이 대체하는 RPA시장이 확장되면서 무궁무진한 가능성을 열었다. 본 연구에서는 RPA tool과 챗봇을 연결해 사무적인 업무를 PC 혹은 모바일로 효율적으로 제어하는 서비스를 제시한다.

Optimization of evaluation system of anti-cancer therapeutic efficacy using optical imaging equipment

Hyungsoo Yuh,Jung Hyu Shin,Ig jun Cho,Hyungho Moon,Jiyeong Bae,Woo-sung Choi,Byunghwa Hyun 한국실험동물학회 2017 한국실험동물학회 학술발표대회 논문집 Vol.2017 No.8

Effects of Dynamic Exercise Program Using Thera-Band on Craniovertebral Angle in Adults with Forward Head Posture

Hyungsoo Shin,Kihyun Kim,Namjin Jung 국제물리치료연구학회 2020 Journal of International Academy of Physical Ther Vol.11 No.1

Background: The alignment of the neck and shoulder is important in people with forward head posture. However, previous studies have mainly conducted fragmentary studies on the neck and shoulders, and studies on the combined movement of the neck and shoulders are incomplete. Objective: To investigate the effects of 6 week dynamic exercise program using Thera-band on craniovertebral angle (CVA) in adults with forward head posture. Design: Quasi-experimental study. Methods: The study was conducted on 24 adults with forward head posture and experimented with neck and shoulder exercises and divided them into groups of neck exercises, shoulder exercises, and neck and shoulder exercises to measure CVA values before and after the experiment. The neck exercise program included flexion and extension muscles of the neck and shoulder exercises included dynamic exercise of the upper extremities such as the trapezius muscles and serratus anterior muscle. The CVA results were measured using PA200. Results: Following the interventions, neck exercise group showed significant improvement in CVA (P<.05), but shoulder exercise group and combined exercise group did not show any significant results (P>.05). However, both groups showed some positive results. Significant differences were seen in the comparisons between the three groups (P<.05), and the results of the posthoc test showed significant differences in neck exercise group and shoulder exercise, neck exercise and combine exercise group. Conclusion: This study suggested that the Thera-band neck exercise is beneficial for foward head posture patients and is expected to be used in clinical trials.