The Distributed & Cloud Computing Lab, directed by Professor Heonchang Yu, was established in 1998 at Korea University. The lab focuses on distributed computing research, including data management, mobility management, fault-tolerant and dependable services, overlay network construction, virtual machine checkpointing and spot instance management, cost-efficient scheduling algorithms, and resource replication.

연세대학교 분산 및 클라우드 컴퓨팅 연구실은 유헌창 교수의 지도하에 1998년에 설립되었으며, 데이터 관리, 이동성 관리, 고장 허용 및 신뢰성 있는 서비스, 오버레이 네트워크 구축, 가상 머신 체크포인팅 및 스팟 인스턴스 관리, 비용 효율적인 스케줄링 알고리즘, 자원 복제 등 분산 컴퓨팅 연구에 중점을 둔다.

Vertical auto-scaling mechanism for elastic memory management of containerized applications in Kubernetes

MkRP: multiple k registry placement for fast container deployment on edge computing

SADDLE: A runtime feedback control architecture for adaptive distributed deep learning in heterogeneous GPU clusters

A-BEE-C: Autonomous Bandwidth-Efficient Edge Codecast

CSS: Container Resource Manager Using System Call Pattern for Scientific Workflow

Fine-Grained I/O Traffic Control Middleware for I/O Fairness in Virtualized System

GPGPU Task Scheduling Technique for Reducing the Performance Deviation of Multiple GPGPU Tasks in RPC-Based GPU Virtualization Environments

I/O Strength-Aware Credit Scheduler for Virtualized Environments

Performance Prediction for convolutional Neural Network on Spark Cluster

Log Analysis-Based Resource and Execution Time Improvement in HPC: A Case Study

Partial migration technique for GPGPU tasks to Prevent GPU Memory Starvation in RPC-based GPU Virtualization

Latency-Classification-Based Deadline-Aware Task Offloading Algorithm in Mobile Edge Computing Environments

Intelligent Resource Management Schemes for Systems, Services, and Applications of Cloud Computing Based on Artificial Intelligence

Evaluation of P2P and cloud computing as platform for exhaustive key search on block ciphers

Mitigation technique for performance degradation of virtual machine owing to GPU pass-through in fog computing

Byzantine-resilient dual gossip membership management in clouds

An Intelligent Residual Resource Monitoring Scheme in Cloud Computing Environments.

A Distributed Snapshot Protocol for Efficient Artificial Intelligence Computation in Cloud Computing Environments

A slave ants based ant colony optimization algorithm for task scheduling in cloud computing environments

An Efficient and Energy-Aware Cloud Consolidation Algorithm for Multimedia Big Data Applications

Detecting Sybil Attacks in Cloud Computing Environments Based on Fail‐Stop Signature

Dynamic Group-based Fault Tolerance Technique for Reliable Resource Management in Mobile Cloud Computing

Task classification based energy-aware consolidation in clouds

A scheduling algorithm with dynamic properties in mobile grid

Fault tolerance and QoS scheduling using CAN in mobile social cloud computing

Scalable and leaderless Byzantine consensus in cloud computing environments

Unstructured deadlock detection technique with scalability and complexity-efficiency in clouds

Mobility-aware balanced scheduling algorithm in mobile grid based on mobile agent

A Workflow Scheduling Technique Using Genetic Algorithm in Spot Instance-Based Cloud.

Task balanced workflow scheduling technique considering task processing rate in spot market

Estimated interval-based checkpointing (EIC) on spot instances in cloud computing

Fault tolerance technique based on monitoring and pattern for reliable resource management in mobile cloud computing

Resource provision technique with entropy-based mobility grouping for fault tolerance in mobile cloud computing

Fault tolerance technique using replication and checkpoint in mobile grid

A deadlock detection algorithm using gossip in cloud computing environments

Enhancing digital fluency through a training program for creative problem solving using computer programming

Performance evaluation of many-core systems: case study with TILEPro64

Pipelined CPU Design With FPGA in Teaching Computer Architecture

Using virtual platform embedded system education

A Termination Detection Technique Using Gossip in Cloud Computing Environments

A Gossip-based Mutual Exclusion Algorithm for Cloud Environments

A Mobile Device Group Based Fault Tolerance Scheduling Algorithm in Mobile Grid

FRAsystem: Fault tolerant system using agents in distributed computing systems

An Efficient Checkpointing Scheme Using Price History of Spot Instances in Cloud Computing Environment

Replication and Checkpoint Schemes for Task-Fault Tolerance in Campus-Wide Mobile Grid

Adaptive Service Scheduling for Workflow Applications in Service-Oriented Grid

Monitoring Service Using Markov Chain Model in Mobile Grid Environment

Agent-Based Autonomous Result Verification Mechanism in Desktop Grid Systems

An Effective Job Replication Technique Based on Reliability and Performance in Mobile Grids

Genetic Algorithm Based Scheduling Method for Efficiency and Reliability in Mobile Grid

Performance Evaluation of Scheduling Mechanism with Checkpoint Sharing and Task Duplication in P2P-Based PC Grid Computing

Imaged document text retrieval without OCR

Advanced obfuscation techniques for Java bytecode

Arterial stiffness is associated with diabetic retinopathy in Korean type 2 diabetic patients

Iodine nutrition and the prevalence of thyroid disease after salt iodization: a cross-sectional survey in Shanghai, a coastal area in China

Markov chain based monitoring service for fault tolerance in mobile cloud computing

Display apparatus

Factors associated with the presence and severity of diabetic ketoacidosis at diagnosis of type 1 diabetes in Korean children and adolescents.

Chinese clothing

Volunteer availability based fault tolerant scheduling mechanism in desktop grid computing environment

Prevalence of thyroid nodules and its relationship with iodine status in Shanghai: a population-based study

Pipelined cpu design with fpga in teaching computer architecture

A carcinoid tumor of the ampulla of Vater treated by endoscopic snare papillectomy

Clinical and laboratory characteristics of neonatal hypocalcemia

A resource management and fault tolerance services in grid computing

Association of birth defects with the mode of assisted reproductive technology in a Chinese data-linkage cohort

Nanotubes and nanosheets

초중등 단계 Computational Thinking 도입을 위한 기초연구

Joon-Min Gil

Heonchang Yu

We propose a method for text retrieval from document images without the use of OCR. Documents are segmented into character objects. Image features, namely the vertical traverse density (VTD) and horizontal traverse density (HTD), are extracted. An n-gram-based document vector is constructed for each document based on these features. Text similarity between documents is then measured by calculating the dot product of the document vectors. Testing with seven corpora of imaged textual documents in English and Chinese as well as images from the UW1 (University of Washington 1) database confirms the validity of the proposed method.

There exist several obfuscation tools for preventing Java bytecode from being decompiled. Most of these tools simply scramble the names of the identifiers stored in a bytecode by substituting the identifiers with meaningless names. However, the scrambling technique cannot deter a determined cracker very long. We propose several advanced obfuscation techniques that make Java bytecode impossible to recompile or make the decompiled program difficult to understand and to recompile. The crux of our approach is to over use an identifier. That is, an identifier can denote several entities, such as types, fields, and methods, simultaneously. An additional benefit is that the size of the bytecode is reduced because fewer and shorter identifier names are used. Furthermore, we also propose several techniques to intentionally introduce syntactic and semantic errors into the decompiled program while preserving the …

Since cloud computing provides computing resources on a pay per use basis, a task scheduling algorithm directly affects the cost for users. In this paper, we propose a novel cloud task scheduling algorithm based on ant colony optimization that allocates tasks of cloud users to virtual machines in cloud computing environments in an efficient manner. To enhance the performance of the task scheduler in cloud computing environments with ant colony optimization, we adapt diversification and reinforcement strategies with slave ants. The proposed algorithm solves the global optimization problem with slave ants by avoiding long paths whose pheromones are wrongly accumulated by leading ants.

Objectives We evaluated the association between common carotid artery intima-media thickness (CCA-IMT), brachial-ankle pulse wave velocity (baPWV), carotid plaque, and peripheral arterial disease (PAD) as indicators of macroangiopathy and diabetic retinopathy as an indicator of microangiopathy in type 2 diabetic patients. Methods We analyzed 605 type 2 diabetic patients registered at a public health center in Korea. Following overnight fasting, venous blood and urine samples were collected and analyzed. The CCA-IMT, levels of carotid plaque, baPWV, and ankle-brachial index (ABI) of the subjects were assessed. We used non-mydriatic fundus photography to diagnose diabetic retinopathy. Multiple logistic regression analyses were used to evaluate the association between macroangiopathy and diabetic retinopathy. CCA-IMT and baPWV were divided into tertiles: CCA-IMT, 0.39 to 0.65 mm, 0.66 to 0.78 …

Background Both insufficient and excess iodine may produce thyroid disease. After salt iodization in China, the median urine iodine concentration (UIC) of children aged 8–10 years appeared adequate. However, it is unknown whether dietary changes due to rapid economic development in Shanghai have affected whole population iodine nutrition. Objective To assess dietary iodine intake, UIC and the prevalence of thyroid disease in the general population of Shanghai. Design A cross-sectional survey was conducted with general participants aged 5–69 years (n = 7,904) plus pregnant and lactating women (n = 380 each) selected by stratified multistage sampling. The iodine concentrations in their salt, drinking water and urine were measured. Daily iodine intake was estimated using the total diet study approach. Serum thyroid hormone concentrations and thyroid-related antibodies were measured and thyroid ultrasonography was performed. Results The median iodine concentration in salt was 29.5 mg/kg, and 12.8 µg/L in drinking water. Iodized salt, used by 95.3% of participants, contributed 63.5% of total dietary iodine. Estimated daily iodine intake was 225.96 µg. The median UIC of general participants was 146.7 µg/L; UIC <100 µg/L (iodine insufficiency) was seen in 28.6%; UIC >300 µg/L (iodine excess) in 10.1%. Pregnant women had a median UIC of 135.9 µg/L, with UIC <150 µg/L in 55.4%. Thyroid nodules and subclinical hypothyroidism were found in 27.44% and 9.17%, respectively. Conclusions According to published criteria, the …

Mobile cloud computing is a combination of mobile computing and cloud computing, and provides cloud computing environment through various mobile devices. Recently, due to rapid expansion of smart phone market and wireless communication environment, mobile devices are considered as resource for large scale distributed processing. But mobile devices have several problems, such as unstable wireless connection, limitation of power capacity, low communication bandwidth and frequent location changes. As resource providers, mobile devices can join and leave the distributed computing environment unpredictably. This interrupts the undergoing operation, and the delay or failure of completing the operation may cause a system failure. Because of low reliability and no-guarantee of completing an operation, it is difficult to use a mobile device as a resource. That means that mobile devices are volatile …

The purpose of this paper is to propose a training program for creative problem solving based on computer programming. The proposed program will encourage students to solve real‐life problems through a creative thinking spiral related to cognitive skills with computer programming. With the goal of enhancing digital fluency through this proposed training program, we investigated its effects. Two sets of experiments were performed in which 119 typical students and 30 younger, gifted students participated. Two synthetic creative problem solving tests, which had a high correlation with logical ability, scientific problem solving ability and divergent thinking ability, were developed to measure creative problem solving ability. We provided the treatment group with a paper‐based booklet with relevant problems developed specifically for that group. ANCOVA statistical procedures were used to analyze the pre‐ and post …

Provided is a display apparatus. The display apparatus includes a display panel for displaying an image, a back cover mounted on a rear Surface of the display panel, and a curva ture adjustment unit mounted on the rear Surface of the back cover to adjustment a curvature of the back cover according to user's manual manipulation.

The aim of this study was to identify the risk factors for presence and severity of diabetic ketoacidosis (DKA) at the onset of type 1 diabetes mellitus (T1DM) in Korean children and adolescents. A retrospective chart review of children and adolescents newly diagnosed with T1DM was conducted in seven secondary and tertiary centers in Korea. Eligible subjects were< 20 years of age and had records on the presence or absence of DKA at the time of T1DM diagnosis. DKA severity was categorized as mild, moderate, or severe. Data were collected on age, height, body weight, pubertal status, family history of diabetes, delayed diagnosis, preceding infections, health insurance status, and parental education level. A total of 361 patients (male 46.3%) with T1DM were included. Overall, 177 (49.0%) patients presented with DKA at T1DM diagnosis. Risk factors predicting DKA at T1DM diagnosis were age≥ 12 years, lower serum C-peptide levels, presence of a preceding infection, and delayed diagnosis. Low parental education level and preceding infection increased the severity of DKA. These results suggest that alertness of the physician and public awareness of diabetes symptoms are needed to decrease the incidence and severity of DKA at T1DM diagnosis.

Chinese clothing has undergone continuous transformations throughout history, providing a reflection of the culture in place at any given time. A wealth of archaeological findings coupled with ancient mythology, poetry and songs enable us to see the development of distinctive Chinese fashions through the ages. This illustrated introductory survey takes the reader through traditional Chinese clothing, ornamentation and ceremonial wear, discusses the importance of silk and the diverse costumes of China's ethnic groups before considering modern trends and China's place in the fashion world today.

Fault tolerance is essential to the further development of desktop grid computing system in order to guarantee continuous and reliable execution of tasks in spite of failures. In a desktop grid computing environment, volunteers are often susceptible to volunteer autonomy failures such as volatility failure and interference failure in the middle of execution of tasks because a desktop grid computing maximally respects autonomy of volunteers. The failures result in an independent livelock problem (i.e. the delay and blocking of the entire execution of a job). Therefore, the failures should be considered in a scheduling mechanism. In This work, in order to tolerate volunteer autonomy failures, we propose a new fault tolerant scheduling mechanism. First, we specify a volunteer autonomy failures and an independent livelock problem. Then, we propose a volunteer availability which reflects the degree of volunteer autonomy …

Objective This study was designed to evaluate the prevalence of thyroid nodules (TNs) and its relationship with urine iodine concentrations (UICs) after the regional rapid economic growth and lifestyle changes. Methods A cross-sectional survey was conducted in the general population aged 15-69 years. A questionnaire regarding general and personal characteristics and relevant information was administered. Ultrasonography of the thyroid was performed, and serum triiodothyronine (T3), tetraiodothyronine (T4), serum thyroid stimulating hormone (TSH), free triiodothyronine (FT3), free tetraiodothyronine (FT4), thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb), and TSH receptor antibody (TRAb) levels were measured for each individual subject. Results The prevalence rates of TNs in the whole population, females and males were 27.76%, 34.04%, and 21.60%, respectively. The prevalence of …

This paper presents a pipelined CPU design project with a field programmable gate array (FPGA) system in a computer architecture course. The class project is a five-stage pipelined 32-bit MIPS design with experiments on the Altera DE2 board. For proper scheduling, milestones were set every one or two weeks to help students complete the project on time. The goal of the project is to educate students effectively via hands-on learning, rather than having them achieve a complete and flawless CPU design. This study reveals that 21 MIPS instructions are enough to achieve the purpose. With the addition in 2010 of the properly enforced scheduling and the FPGA system, many more students successfully completed the class project than was the case in 2009. A student survey and the independent samples t-test reveal the effectiveness of the methodology with the FPGA system. This work differs from previous work in …

Here, a case of a patient with incidental finding of a carcinoid tumor of the ampulla of Vater, who was treated with endoscopic snare papillectomy, is reported. A 62-year-old male was admitted to our hospital due to a carcinoid tumor of the ampulla of Vater, which was found during follow-up endoscopy after an endoscopic mucosal resection of early gastric cancer. No lymphadenopathy or visceral metastasis was found on an abdominal CT scan, In-111 octerotide scan and EUS. The ampulla was then en bloc removed by endoscopic snare papillectomy. The resected specimen revealed a 0.7×0.5×0.1 cm sized carcinoid tumor. All margins of resection were negative for tumor. After six months of follow-up, there was no evidence of recurrence and metastasis, either endoscopically or radiologically. To our knowledge, this case is the first report of an ampullary carcinoid tumor treated by endoscopic snare papillectomy in …

Purpose To describe the clinical characteristics of full-term neonates with hypocalcemia and to suggest factors associated with neonatal hypocalcemia Methods The medical records of full-term neonates with hypocalcemia were reviewed. Hypocalcemia was defined as an ionized calcium (iCa) concentration of <4 mg/dL. Parathyroid hormone (PTH) insufficiency was defined as a serum PTH level of <60 pg/mL or a serum phosphorus level higher than the serum calcium level in the presence of hypocalcemia. Results Fifty-three neonates were enrolled. The median age at diagnosis of hypocalcemia was 3 days. In all the neonates, formula feeding predominance was observed. Thirty-eight neonates (69.8%) were compatible with PTH insufficiency. The number of formula-fed neonates was significantly higher than that of breast-fed patients among neonates with PTH insufficiency ( P =0.017). Intact PTH was negatively correlated with serum phosphorus levels. Twelve out of 14 neonates (85.7%) had 25-hydroxy vitamin D (25OHD) levels <20 ng/mL and 9 neonates (64.3%) had 25OHD levels <10 ng/mL. Twenty-one neonates had hypocalcemic tetany. The serum calcium and iCa concentrations of neonates with tetany were 4.2-8.3 mg/dL and 1.85-3.88 mg/dL, respectively. Three neonates showed symptomatic hypocalcemia with calcium levels over 7.5 mg/dL. Among the 16 neonates who underwent electroencephalography (EEG), 12 had abnormalities, which normalized after 1-2 months. Conclusion Formula milk feeding, PTH insufficiency and low serum vitamin D concentration are associated with the development of neonatal hypocalcemia. Symptoms …

In grid computing, resource management and fault tolerance services are important issues. The availability of the selected resources for job execution is a primary factor that determines the computing performance. In this paper, we propose a resource manager for optimal resource selection. Our resource manager automatically selects the set of optimal resources among candidate resources that achieves optimal performance using a genetic algorithm. Typically, the probability of a failure is higher in the grid computing than in a traditional parallel computing and the failure of resources affects job execution fatally. Therefore, a fault tolerance service is essential in computational grids. And grid services are often expected to meet some minimum levels of Quality of Service (QoS) for a desirable operation. To address this issue, we also propose a fault tolerance service that satisfies QoS requirements. We extend the …

Objective To evaluate the impact of assisted reproductive technology (ART) on the offspring of Chinese population. Design Retrospective, data-linkage cohort. Setting Not applicable. Patient(s) Live births resulting from ART or natural conception. Intervention(s) None. Main Outcome Measure(s) Birth defects coded according to ICD-10. Result(s) Births after ART were more likely to be female and multiple births, especially after intracytoplasmic sperm injection (ICSI). ART was associated with a significantly increased risk of birth defects, especially, among singleton births, a significantly increased risk in fresh-embryo cycles after in vitro fertilization (IVF) and frozen-embryo cycles after ICSI. Associations between ART and multiple defects, between ART and gastrointestinal malformation, genital organs malformation, and musculoskeletal malformation among singleton births, and between ART and cardiac septa malformation …

This book is among the first to focus exclusively on the research and development of boron nitride (BN) nanosheets, also known as white graphene, a remarkable two‑dimensional nanoma‑terial. It provides a comprehensive exploration of their structure, synthesis methods, properties, and diverse applications in energy storage, thermal management, and environmental solutions. Each chapter is authored by internationally recognized experts with extensive experience in BN nanomaterials. Structurally similar to graphene, BN nanosheets possess unique properties, including excep‑tional thermal and chemical stability, electrical insulation with high thermal conductivity, and distinctive catalytic surface chemistry. BN nanosheets have paved the way for numerous ground‑breaking applications and offer innovative solutions to critical industrial and environmental challenges—providing advantages that graphene alone …

The performance of mobile devices including smart phones and laptops is steadily rising as prices plummet sharply. So, mobile devices are changing from being a mere interface for requesting services to becoming computing resources for providing and sharing services due to immeasurably improved performance. With the increasing number of mobile device users, the utilization rate of SNS (Social Networking Service) is also soaring. Applying SNS to the existing computing environment enables members of social network to share computing services without further authentication. To use mobile device as a computing resource, temporary network disconnection caused by user mobility and various HW/SW faults causing service disruption should be considered. Also these issues must be resolved to support mobile users and to provide user requirements for services. Accordingly, we propose fault tolerance and QoS …

Department of Computer Science and Engineering, College of Informatics

D&C Lab.

교수님 소개

유헌창

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Vertical auto-scaling mechanism for elastic memory management of containerized applications in Kubernetes

MkRP: multiple k registry placement for fast container deployment on edge computing

SADDLE: A runtime feedback control architecture for adaptive distributed deep learning in heterogeneous GPU clusters

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

유헌창

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Vertical auto-scaling mechanism for elastic memory management of containerized applications in Kubernetes

MkRP: multiple k registry placement for fast container deployment on edge computing

SADDLE: A runtime feedback control architecture for adaptive distributed deep learning in heterogeneous GPU clusters

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집