publications

2024

1. SAC

   Rescuing QUIC Flows From Countermeasures Against UDP Flooding Attacks

   Junseok Lee, Minhyeong Kim, Wonjun Song, and 2 more authors

   In Proceedings of the 39th ACM/SIGAPP Symposium on Applied Computing, 2024

   Abs Bib Best paper

   Due to advantages such as quick connection establishment and multiple streaming over a single connection, QUIC was included in the new standard of HTTP 3.0 as an alternative transport layer protocol. Since QUIC operates on UDP, however, QUIC flows can be blocked by existing countermeasures against UDP flooding attacks, even if transmission rates are fairly controlled by congestion control algorithms, such as TCP. In this paper, we confirm that such a problem arises in real-world Internet environment and design effective approaches to avoid it. In the first approach, the gateway router dynamically sets the rate limit for the QUIC flow, based on the expected next CWND size estimated by the receiver using a built-in congestion control algorithm. The second approach leverages the proactive dropping of packets (or ECN marking) to distinguish whether the flow is a self-regulated QUIC flow or an unresponsive UDP attack/selfish flow. Simulation studies using the ns-3 simulator confirm that the proposed approaches can selectively allow QUIC flows regardless of their short-term transmission rates while preserving the effectiveness of existing countermeasures against UDP flooding attacks.

   @inproceedings{lee2024rescuing,
     title = {Rescuing QUIC Flows From Countermeasures Against UDP Flooding Attacks},
     author = {Lee, Junseok and Kim, Minhyeong and Song, Wonjun and Kim, Younghoon and Kim, Dohyung},
     booktitle = {Proceedings of the 39th ACM/SIGAPP Symposium on Applied Computing},
     pages = {1072--1080},
     year = {2024},
     organization = {ACM/SIGAPP},
     award = {Our team received the best paper award in ACM SAC 2024 - https://www.sigapp.org/sac/sac2024/},
     award_name = {Best paper},
   }

   Our team received the best paper award in ACM SAC 2024 - https://www.sigapp.org/sac/sac2024/

2. T-IV

   What If Vehicles are Controlled by the Road?

   Junhyeok Hwang, Keun-Woo Lim, and Dohyung Kim

   IEEE Transactions on Intelligent Vehicles, 2024

   Abs Bib

   Recently, self-driving vehicles have been actively studied and have begun to operate on actual roads. Most of the current self-driving vehicles rely on a number of sensors to individually judge the situation and take action. However, from a road perspective, a collection of individual vehicles’ decisions is inevitably sub-optimal, and it is essential that roads directly intervene (control/assist) in vehicle operation for optimal traffic management. This paper proposes Software-Defined Traffic Management (SDTM) that incorporates the concept of Software-Defined Networking (SDN) into the transportation environment. In SDTM, each vehicle is handled like a packet in SDN and its movement can be assisted/controlled using a global view of the road. To this end, SDTM enables reliable interaction between vehicles and infrastructure (RSU/controller) by 1) allocating collision-free channels to vehicles, 2) reducing vehicle’s messaging interval by fully utilizing available channel resources, and 3) redistributing sensitive information from the infrastructure. Based on the traffic information collected and reported by RSU, the controller induces vehicle to form clusters and controls/assists the movement of vehicles on a cluster-by-cluster basis, implementing safe and efficient traffic flows. According to the performance evaluation using the ns-3 simulator, under SDTM, vehicles experience an average travel time reduced by 30% (more than 97% of all vehicles experience shorter travel time) compared to the real traffic traces, while maintaining a safety distance.

   @article{hwang2024if,
     title = {What If Vehicles are Controlled by the Road?},
     author = {Hwang, Junhyeok and Lim, Keun-Woo and Kim, Dohyung},
     journal = {IEEE Transactions on Intelligent Vehicles},
     year = {2024},
     publisher = {IEEE},
   }

2022

1. SAC

   RepCoder: an automated program repair framework for probability-based program synthesis

   Suhwan Ji, Sang-Min Choi, Sang-Ki Ko, and 2 more authors

   In Proceedings of the 37th ACM/SIGAPP Symposium on Applied Computing, 2022

   Abs Bib

   Recently, machine learning-based automated program synthesis and repair have extensively been investigated for various domain-specific and general-purpose programming languages. In this paper, we revisit the problem of synthesizing programs from input-output examples, and reformulate it as a problem of program repair. More specifically, we propose an automated program repair framework, called RepCoder, that can be used with a neural program synthesis method such as DeepCoder and PCCoder. Given a set of input-output examples and a user program with some errors, RepCoder effectively reduces the search space by considering user-written statements to be correct with high likelihood if they are included in the top-k candidate statements predicted by the employed neural synthesis method. Otherwise, they are considered to be incorrect and replaced with the candidate statements with the highest probabilities that are consistent with the given input-output examples. Our experimental studies confirm that RepCoder using PCCoder as the main predictor effectively and efficiently repairs erroneous programs, showing that it achieves up to 3× the error correction rate compared to when using only PCCoder for repair, i.e., synthesizing a program from scratch without considering the given user program.

     title = {RepCoder: an automated program repair framework for probability-based program synthesis},
     author = {Ji, Suhwan and Choi, Sang-Min and Ko, Sang-Ki and Kim, Dohyung and Im, Hyeonseung},
     booktitle = {Proceedings of the 37th ACM/SIGAPP Symposium on Applied Computing},
     pages = {1554--1561},
     year = {2022},
     organization = {ACM/SIGAPP}
   }

2021

1. Access

   Evaluating countermeasures for verifying the integrity of Ethereum smart contract applications

   Suhwan Ji, Dohyung Kim, and Hyeonseung Im

   IEEE Access, 2021

   Abs Bib

   Blockchain technology, which provides digital security in a distributed manner, has evolved into a key technology that can build efficient and reliable decentralized applications (called DApps) beyond the function of cryptocurrency. The characteristics of blockchain such as immutability and openness, however, have made DApps more vulnerable to various security risks, and thus it has become of great significance to validate the integrity of DApps before they actually operate upon blockchain. Recently, research on vulnerability in smart contracts (a building block of DApps) has been actively conducted, and various vulnerabilities and their countermeasures were reported. However, the effectiveness of such countermeasures has not been studied well, and no appropriate methods have been proposed to evaluate them. In this paper, we propose a software tool that can easily perform comparative studies by adding existing/new countermeasures and labeled smart contract codes. The proposed tool demonstrates verification performance using various statistical indicators, which helps to identify the most effective countermeasures for each type of vulnerability. Using the proposed tool, we evaluated state-of-the-art countermeasures with 237 labeled benchmark codes. The results indicate that for certain types of vulnerabilities, some countermeasures show evenly good performance scores on various metrics. However, it is also observed that countermeasures that detect the largest number of vulnerable codes typically generate much more false positives, resulting in very low precision and accuracy. Consequently, under given constraints, different countermeasures may be recommended for detecting vulnerabilities of interest. We believe that the proposed tool could effectively be utilized for a future verification study of smart contract applications and contribute to the development of practical and secure smart contract applications.

   @article{ji2021evaluating,
     title = {Evaluating countermeasures for verifying the integrity of Ethereum smart contract applications},
     author = {Ji, Suhwan and Kim, Dohyung and Im, Hyeonseung},
     journal = {IEEE Access},
     volume = {9},
     pages = {90029--90042},
     year = {2021},
     publisher = {IEEE}
   }

2020

1. TPDS

   T-caching: Enhancing feasibility of in-network caching in ICN

   Sugi Lee, Ikjun Yeom, and Dohyung Kim

   IEEE Transactions on Parallel and Distributed Systems, 2020

   Abs Bib

   In Information-Centric Networking (ICN), in-network caching is one of the core functions to implement efficient content distribution. As content is served from the network cache, redundant transmission across the same link is reduced and better quality services are provided to the user. However, caching operations (locating cached content, validating/writing content to the cache) may be a large burden on routers. In this article, we substantially reduce the caching overhead of routers by introducing T-Caching, a new in-network caching model in which routers selectively cache some of the most popular content recommended by content providers. In T-Caching, tokens are used 1) to enable routers to maximize caching benefits by simply controlling the amount of content inserted into the cache; 2) to allow content providers to recommend the most popular content as much as routers would actually cache. Our simulation and empirical studies using synthetic data, as well as real-world traces, show that T-Caching allows routers to insert much less than 1 percent of the content into the cache, compared to typical caching mechanisms. Nevertheless, the cache-hit ratio is improved by up to 2\~9 times depending on the cache size. We believe that T-Caching can significantly contribute to improving feasibility and performance of in-network caching in ICN.

   @article{lee2020t,
     title = {T-caching: Enhancing feasibility of in-network caching in ICN},
     author = {Lee, Sugi and Yeom, Ikjun and Kim, Dohyung},
     journal = {IEEE Transactions on Parallel and Distributed Systems},
     volume = {31},
     number = {7},
     pages = {1486--1498},
     year = {2020},
   }

2. TIIS

   An Overview of Content Poisoning in NDN: Attacks, Countermeasures, and Direction.

   Hyeonseung Im, and Dohyung Kim

   KSII Transactions on Internet & Information Systems, 2020

   Abs Bib

   With a huge demand for replicated content on the Internet, a new networking paradigm called information-centric networking (ICN) has been introduced for efficient content dissemination. In ICN, named content is distributed over the network cache and it is accessed by name instead of a location identifier. These aspects allow users to retrieve content from any of the nodes having replicas, and consequently 1) network resources are more efficiently utilized by avoiding redundant transmission and 2) more scalable services are provided by distributing server loads. However, in-network caching in ICN brings about a new type of security issues, called content poisoning attacks, where fabricated content is located in the network cache and interferes with the normal behavior of the system. In this paper, we look into the problems of content poisoning in ICN and discuss security architectures against them. In particular, we reconsider the state-of-the-art schemes from the perspective of feasibility, and propose a practical security architecture.

   @article{im2020overview,
     title = {An Overview of Content Poisoning in NDN: Attacks, Countermeasures, and Direction.},
     author = {Im, Hyeonseung and Kim, Dohyung},
     journal = {KSII Transactions on Internet \& Information Systems},
     volume = {14},
     number = {7},
     year = {2020}
   }

3. TVT

   Implementing distributed TDMA using relative distance in vehicular networks

   Yafeng Deng, Dohyung Kim, Zhetao Li, and 1 more author

   IEEE Transactions on Vehicular Technology, 2020

   Abs Bib

   With the advent of self-driving cars, vehicular networking is gaining greater attention and the subject of extensive research. It is important to implement a more efficient and secure transportation system by enabling communication among objects on the road. Specifically, safety applications should be delivered in a reliable manner within a limited time period. Several time division multiple access (TDMA) protocols have been proposed to realize this. However, most of the existing research have proposed slot management approaches by taking into account the static topology; they have not sufficiently discussed research on “merging collision” arising from overlapping two or more collision domains due to vehicle mobility. In this study, we examine the effect of merging collision in terms of packet delivery ratio, overhead, and inter-basic safety message (inter-BSM) delay. Delay between BSMs received in succession. To mitigate the effect of merging collision, we also propose a lightweight distributed TDMA protocol, where the order of vehicles on the road and their relative distances are exploited to determine the dedicated slot. The collision is further resolved using in-band signaling from the surrounding vehicles. Simulation studies show that the proposed scheme improves the performance of the packet delivery ratio (PDR) 10% more than the comparative protocol, and consequently achieves 97% and 95% PDRs, in highway and urban environment, respectively. Furthermore, the overhead and inter-BSM delay are substantially reduced.

   @article{deng2020implementing,
     title = {Implementing distributed TDMA using relative distance in vehicular networks},
     author = {Deng, Yafeng and Kim, Dohyung and Li, Zhetao and Choi, Young-June},
     journal = {IEEE Transactions on Vehicular Technology},
     volume = {69},
     number = {7},
     pages = {7295--7305},
     year = {2020},
     publisher = {IEEE}
   }

2019

1. ICCCN

   When blockchain takes care of the OLSR network

   May Thura Lwin, Young-Bae Ko, and Dohyung Kim

   In 2019 28th International Conference on Computer Communication and Networks (ICCCN), 2019

   Abs Bib

   Over the several years, lots of researches have focused on routing protocol for Mobile Ad-Hoc Networks (MANET). Optimized Link State Routing Protocol (OLSR) is one of the typical routing protocols standardized by IETF, but it is known to be vulnerable to many type of security attacks. In this paper, blockchain technology is applied to OLSR to complement security vulnerabilities and reduce the computational overhead in existing security solutions.

   @inproceedings{lwin2019blockchain,
     title = {When blockchain takes care of the OLSR network},
     author = {Lwin, May Thura and Ko, Young-Bae and Kim, Dohyung},
     booktitle = {2019 28th International Conference on Computer Communication and Networks (ICCCN)},
     pages = {1--2},
     year = {2019},
     organization = {IEEE}
   }

2. SAC

   Energy-aware medium access control for energy-harvesting machine-to-machine networks

   Dohyung Kim, and Youngbae Ko

   In Proceedings of the 34th ACM/SIGAPP Symposium on Applied Computing, 2019

   Abs Bib

   Energy-harvesting is being actively researched for the Machine-to-Machine networks. Without replacement of battery, energy-harvesting enables nodes (or machines) to perform their work permanently by recharging energy store periodically from an external source. After performing given tasks, in many applications, each energy-harvesting node transmits data to the gateway node. Here, the difference in harvested/consumed energy could lead to sub-optimal communication due to depletion of energy. In this paper, we design an energy-aware medium access control scheme for energy-harvesting machine-to-machine networks. The proposed algorithm controls delivery error rate due to energy depletion through limited contention among energy-exhausting nodes, and maximize slot efficiency to minimize overall communication duration. Maximizing slot efficiency is implemented in two ways: utility-based and learning-based. Simulation studies have shown that the proposed schemes effectively minimize delivery error rate and communication period, outperforming the existing strategies in the literature.

   @inproceedings{kim2019energy,
     title = {Energy-aware medium access control for energy-harvesting machine-to-machine networks},
     author = {Kim, Dohyung and Ko, Youngbae},
     booktitle = {Proceedings of the 34th ACM/SIGAPP Symposium on Applied Computing},
     pages = {2399--2405},
     year = {2019},
     organization = {ACM/SIGAPP}
   }

2018

1. ICTC

   A stepwise approach for energy efficient trust evaluation in military IoT networks

   Jihun Lim, Young-Bae Ko, Dohyung Kim, and 1 more author

   In 2018 International Conference on Information and Communication Technology Convergence (ICTC), 2018

   Abs Bib

   In this paper, we address the trust management issue in a military IoT networks where nodes are deployed in harsh and hostile area and communicates. In particular, due to the limited resources of the node, it is of great importance to detect and isolate malicious nodes in an energy-efficient way. Most previous work adopts proactive scanning method that periodically exchanges control messages and does computation for updating trust values over the network, which may incur a waste of energy when no attack is being launched in the network. Here, we present an stepwise approach trust evaluation method using a tree structured routing, in which 1) the trust evaluation process is triggered by nodes only when they sense a suspicious behavior of their child nodes; 2) The evaluation process consists of two phases: querying to its parent node, and local computation of the trust value; Via simulation study using OPNET simulator, it is proven that compared to the existing work, the proposed scheme could achieve the same level of security with much less energy consumption.

   @inproceedings{lim2018stepwise,
     title = {A stepwise approach for energy efficient trust evaluation in military IoT networks},
     author = {Lim, Jihun and Ko, Young-Bae and Kim, Dohyung and Kim, Dabin},
     booktitle = {2018 International Conference on Information and Communication Technology Convergence (ICTC)},
     pages = {689--692},
     year = {2018},
     organization = {IEEE}
   }

2. ICCCN

   ICN-based light-weighted mobility support in IoT

   Donghyeok An, and Dohyung Kim

   In 2018 27th International Conference on Computer Communication and Networks (ICCCN), 2018

   Abs Bib

   In Information-Centric Networking (ICN), name-based addressing and in-network caching allow content to be efficiently distributed/accessed. These properties of ICN have been researched in the arena of wireless domain to implement light-weighted communication protocols. In this paper, specifically, we present an ICN-based content delivery scheme for Internet-of-Things (IoT), and show how the proposed scheme support seamless hand-off.

   @inproceedings{an2018icn,
     author = {An, Donghyeok and Kim, Dohyung},
     booktitle = {2018 27th International Conference on Computer Communication and Networks (ICCCN)},
     pages = {1--2},
     year = {2018},
     organization = {IEEE}
   }

3. IJCS

   Mitigating tail latency in IEEE 802.11–based networks

   Dohyung Kim, Ikjun Yeom, and Tae-Jin Lee

   International Journal of Communication Systems, 2018

   Abs Bib

   Delay sensitive applications are being actively introduced with the advent of 5G and vehicular communications, and such applications are very sensitive to tail latency. However, tail latency has not been seriously considered so far, especially in IEEE 802.11–based networks. Channel access is scheduled by random Contention Window (CW) values in IEEE 802.11–based networks, and the node with the larger CW waits longer, and it may even observe multiple transmissions from a single contending node, which results in a long latency tail. In this paper, we propose a new decentralized MAC called SynchMAC to mitigate this latency tail. In SynchMAC, every competing node transmits exactly one packet within a virtual time slot without a centralized controller. Using the proposed approach, the maximum channel access latency is bounded by T×2N, where T is the time required for transmitting a single packet (including Inter-Frame Space and CW) and N is the number of competing nodes. To maximize the system throughput, the proposed scheme optimizes the value of T by considering the probability of successful transmission. Our simulation study shows that SynchMAC reduces the maximum access latency by up to 94% and 53% compared with the conventional IEEE 802.11 MAC and the comparative scheme, respectively, without degrading throughput performance. We also show that SynchMAC is easily extended to support weighted access.

   @article{kim2018mitigating,
     title = {Mitigating tail latency in IEEE 802.11--based networks},
     author = {Kim, Dohyung and Yeom, Ikjun and Lee, Tae-Jin},
     journal = {International Journal of Communication Systems},
     volume = {31},
     number = {1},
     pages = {e3404},
     year = {2018},
     publisher = {Wiley Online Library}
   }

4. WCL

   Pre-processing images for enhancing reliability in screen-to-camera communication

   Younghoon Kim, Dohyun Lee, and Dohyung Kim

   IEEE Wireless Communications Letters, 2018

   Abs Bib

   In this letter, we discuss an essential part of screen-camera communication, the orientation of the received image, and report reliability problems due to the angle and distance. According to our analyses, communication range could be broadened if an image is proactively manipulated before being displayed according to the locations of both a screen and a camera. By implementing a simple application, we prove that the proposed scheme outperforms the existing ones in terms of throughput, reliability and coverage.

   @article{kim2018pre,
     title = {Pre-processing images for enhancing reliability in screen-to-camera communication},
     author = {Kim, Younghoon and Lee, Dohyun and Kim, Dohyung},
     journal = {IEEE Wireless Communications Letters},
     volume = {7},
     number = {6},
     pages = {934--937},
     year = {2018},
     publisher = {IEEE}
   }

2017

1. VNC

   Receiver-driven broadcast for vehicular applications

   Dohyung Kim, Ikjun Yeom, and Tae-Jin Lee

   In 2017 IEEE Vehicular Networking Conference (VNC), 2017

   Abs Bib

   Broadcasting/multicasting may be an efficient way to disseminate delay-sensitive content in vehicular networks. However, conventional broadcasting schemes have suffered from reliability issues, since they cannot go along with ACK and RTS/CTS. In this paper, we design a novel receiver-driven broadcast scheme for periodic messaging in vehicular applications, where receivers request broadcasting to their neighbors and data is broadcast as a response. Via simulation study, it is shown that the proposed scheme effectively 1) controls contention and 2) mitigates hidden node effects in broadcast communication.

   @inproceedings{kim2017receiver,
     title = {Receiver-driven broadcast for vehicular applications},
     author = {Kim, Dohyung and Yeom, Ikjun and Lee, Tae-Jin},
     booktitle = {2017 IEEE Vehicular Networking Conference (VNC)},
     pages = {239--242},
     year = {2017},
     organization = {IEEE}
   }

2. ICTC

   Network based vByod scheme in NFV platform

   Jonghwan Kim, Tae-Yeon Kim, and Dohyung Kim

   In 2017 International Conference on Information and Communication Technology Convergence (ICTC), 2017

   Abs Bib

   In this paper, we propose a new type of Virtual Network Function (VNF) scheme to realize the Virtual Bring-Your-Own-Device (vByod) service in NFV platform. The proposed scheme allows users to enjoy more powerful computing resource provided by NFV server, and it also significantly improves service quality in terms of security, mobility, and service delay.

   @inproceedings{kim2017network,
     title = {Network based vByod scheme in NFV platform},
     author = {Kim, Jonghwan and Kim, Tae-Yeon and Kim, Dohyung},
     booktitle = {2017 International Conference on Information and Communication Technology Convergence (ICTC)},
     pages = {1143--1145},
     year = {2017},
     organization = {IEEE}
   }

3. CarSys

   Poster: Receiver-driven semi-broadcast for vehicular applications

   Dohyung Kim, Tae-Jin Lee, and Ikjun Yeom

   In Proceedings of the 2nd ACM International Workshop on Smart, Autonomous, and Connected Vehicular Systems and Services, 2017

   Abs Bib

   Broadcasting/multicasting offers a potential benefit for delay-sensitive applications in vehicular networks, since information could be delivered to multiple receivers simultaneously by a single transmission. However, conventional broadcasting schemes suffer from a problem of reliability, since they cannot go along with ACK and RTS/CTS mechanism at the MAC layer. In this paper, we design a novel receiver-driven semi-broadcast scheme for vehicular applications, where receivers request broadcasting to their neighbors and data is broadcasted as a response. Via the simulation study, it is shown that the proposed scheme allows to 1) receive data without contention, 2) control contention, and 3) mitigate hidden node effects.

     title = {Poster: Receiver-driven semi-broadcast for vehicular applications},
     author = {Kim, Dohyung and Lee, Tae-Jin and Yeom, Ikjun},
     booktitle = {Proceedings of the 2nd ACM International Workshop on Smart, Autonomous, and Connected Vehicular Systems and Services},
     pages = {75--76},
     year = {2017},
     organization = {ACM}
   }

4. TIFS

   Security of cached content in NDN

   Dohyung Kim, Jun Bi, Athanasios V Vasilakos, and 1 more author

   IEEE Transactions on Information Forensics and Security, 2017

   Abs Bib

   In Named-Data Networking (NDN), content is cached in network nodes and served for future requests. This property of NDN allows attackers to inject poisoned content into the network and isolate users from valid content sources. Since a digital signature is embedded in every piece of content in NDN architecture, poisoned content is discarded if routers perform signature verification; however, if every content is verified by every router, it would be overly expensive to do. In our preliminary work, we have suggested a content verification scheme that minimizes unnecessary verification and favors already verified content in the content store, which reduces the verification overhead by as much as 90% without failing to detect every piece of poisoned content. Under this scheme, however, routers are vulnerable to verification attack, in which a large amount of unverified content is accessed to exhaust system resources. In this paper, we carefully look at the possible concerns of our preliminary work, including verification attack, and present a simple but effective solution. The proposed solution mitigates the weakness of our preliminary work and allows this paper to be deployed for real-world applications.

   @article{kim2017security,
     title = {Security of cached content in NDN},
     author = {Kim, Dohyung and Bi, Jun and Vasilakos, Athanasios V and Yeom, Ikjun},
     journal = {IEEE Transactions on Information Forensics and Security},
     volume = {12},
     number = {12},
     pages = {2933--2944},
     year = {2017},
     publisher = {IEEE},
   }

5. CN

   Enhancing NDN feasibility via dedicated routing and caching

   Dohyung Kim, and Younghoon Kim

   Computer networks, 2017

   Abs Bib

   Named-data Networking (NDN) is a new networking regime for efficient content distribution. NDN employs name-based access and in-network caching to implement easy access to content. For that, NDN routers perform named-based routing, packet-level caching, and cache look-up, but these operations impose huge overhead on routers. To solve the feasibility issue of NDN router, in this paper, we propose an alternative architecture where caching and routing are separated. Routers are dedicated to packet routing while the cache server that is installed at every domain takes charge of in-network caching. Requests that have visited the cache server are marked and forwarded without further cache-lookup within the domain. This approach fundamentally relieves routers of heavy burden. Additionally, it introduces following benefits: (1) Huge amount of resource for caching is saved; (2) The effectiveness of in-network caching is improved; (3) The access delay of time-sensitive traffic is minimized. For the proposed architecture, cache look-up is performed via reserved links between the cache server and routers. Therefore, it is important to locate the cache server from the point of installation cost. We address how to place the cache server with the minimum cost, which is proved NP-complete, and present an approximation algorithm. Our simulation study shows that the proposed scheme reduces caching operations by up to 80% while achieving the same caching benefit only with 40% caching space.

   @article{kim2017enhancing,
     title = {Enhancing NDN feasibility via dedicated routing and caching},
     author = {Kim, Dohyung and Kim, Younghoon},
     journal = {Computer networks},
     volume = {126},
     pages = {218--228},
     year = {2017},
     publisher = {Elsevier}
   }

2016

1. ICCE

   Named data networking for infrastructure wireless networks

   Cheoleun Moon, Sungwon Han, Honguk Woo, and 1 more author

   In 2016 IEEE International Conference on Consumer Electronics (ICCE), 2016

   Abs Bib

   Named Data Networking(NDN) has emerged to support content-oriented services that are currently prevalent in the Internet. It successfully minimizes redundant transmission on wired links by adopting name-based access and in-network caching. In this paper, we discuss NDN in the IOT world, and propose its enhancement for efficient usage in IOT.

   @inproceedings{moon2016named,
     title = {Named data networking for infrastructure wireless networks},
     author = {Moon, Cheoleun and Han, Sungwon and Woo, Honguk and Kim, Dohyung},
     booktitle = {2016 IEEE International Conference on Consumer Electronics (ICCE)},
     pages = {343--344},
     year = {2016},
     organization = {IEEE}
   }

2. ICOIN

   Efficient streaming over CoAP

   Gyuhong Choi, Dohyung Kim, and Ikjun Yeom

   In 2016 International conference on information networking (ICOIN), 2016

   Abs Bib

   IoT has emerged to realize the notion of ubiquitous interaction of everything. With the help of IoT, various types of objects including human, machine, and almost all things can communicate with each other via the Internet. However, the current state of the art in IoT technology focuses on the limited application such as signalling and exchange of sensing data. In this paper, we look into the necessity of streaming services in IoT, and present an efficient communication scheme for streaming services in IoT.

   @inproceedings{choi2016efficient,
     title = {Efficient streaming over CoAP},
     author = {Choi, Gyuhong and Kim, Dohyung and Yeom, Ikjun},
     booktitle = {2016 International conference on information networking (ICOIN)},
     pages = {476--478},
     year = {2016},
     organization = {IEEE}
   }

3. Ad Hoc Netw.

   Efficient content delivery in mobile ad-hoc networks using CCN

   Dohyung Kim, Jong-hwan Kim, Cheoleun Moon, and 2 more authors

   Ad Hoc Networks, 2016

   Abs Bib

   Information-centric networking (ICN) is emerging as a future network technology. It has introduced the great advantage of information dissemination with low bandwidth consumption in wired testbed networks. Recently, ICN is also studied for mobile ad-hoc networks environments for efficient content distribution. In the existing works in the literature, broadcast delivery is actively utilized for designing new routing schemes since it seems well fitted to the nature of ICN conceptually. In this paper, we raise questions about this research direction by analysing the performance of reliability and energy efficiency of both broadcast and unicast delivery schemes. Our analysis shows that unicast delivery outperforms broadcast delivery, unless topological changes incur too much packet flooding overhead. Based on this observation, we present a novel energy efficient content distribution scheme that delivers the content in a unicast manner while minimizing flooding overhead by taking advantage of ICN features. Via ns-3 simulation, we compare the performance of the proposed scheme with that of other comparative schemes, and show that the proposed scheme achieves much higher reliability and energy efficiency in content distribution under mobile ad-hoc network environments.

   @article{kim2016efficient,
     title = {Efficient content delivery in mobile ad-hoc networks using CCN},
     author = {Kim, Dohyung and Kim, Jong-hwan and Moon, Cheoleun and Choi, Jeonghwan and Yeom, Ikjun},
     journal = {Ad Hoc Networks},
     volume = {36},
     pages = {81--99},
     year = {2016},
     publisher = {Elsevier},
   }

2015

1. ICTC

   Screen acceleration VNF scheme in NFV for VDI service

   Jonghwan Kim, Kee Seong Cho, Won Ryu, and 1 more author

   In 2015 International Conference on Information and Communication Technology Convergence (ICTC), 2015

   Abs Bib

   As the cloud-based datacenter with SDN (Software Defined Network) enabled has been deployed as a real service platform, NFV (Network Function Virtualization) attracts great attention from many researchers. NFV virtualizes network equipment to implement elastic network service in the cloud. Specifically, in this paper, we propose screen acceleration VNF (Virtual Network Function) scheme that makes VDI (Virtual Desktop Infrastructure) service dynamically operational in the cloud and NFV platform.

   @inproceedings{kim2015screen,
     title = {Screen acceleration VNF scheme in NFV for VDI service},
     author = {Kim, Jonghwan and Cho, Kee Seong and Ryu, Won and Kim, Dohyung},
     booktitle = {2015 International Conference on Information and Communication Technology Convergence (ICTC)},
     pages = {816--818},
     year = {2015},
     organization = {IEEE}
   }

2. ICN

   Efficient content verification in named data networking

   Dohyung Kim, Sunwook Nam, Jun Bi, and 1 more author

   In Proceedings of the 2nd ACM Conference on Information-Centric Networking, 2015

   Abs Bib

   In Named Data Networking, contents are retrieved from network caches as well as the content server by their name. This aspect arises severe security concerns on content integrity. Especially, if poisoned contents lie in the network cache, called content store(CS), interests would be served by the poisoned content rather than they propagate toward the content server. Consequently, users whose interests pass through the contaminated CS cannot access the valid content. In order to resolve the problem, every content is verified before they are inserted into the CS. However, this built-in verification mechanism is not practically feasible due to its huge computational overhead. In this paper, we address problems of content integrity in NDN in details, including how to violate content integrity. We also propose a practical solution that efficiently detects poisoned contents from the CS with minimum overhead. Since the proposed scheme aligns to the basic NDN architecture, it is a practical and effective solution.

   @inproceedings{kim2015efficient,
     title = {Efficient content verification in named data networking},
     author = {Kim, Dohyung and Nam, Sunwook and Bi, Jun and Yeom, Ikjun},
     booktitle = {Proceedings of the 2nd ACM Conference on Information-Centric Networking},
     pages = {109--116},
     year = {2015},
     organization = {ACM},
   }

3. ICOIN

   Content verification in named data networking

   SunWook Nam, Dohyung Kim, and Ikjun Yeom

   In 2015 International Conference on Information Networking (ICOIN), 2015

   Abs Bib

   It is crucial to guarantee content integrity in Named Data Networking(NDN), where copies of the contents are distributed over the network. NDN adopts digital signatures, and contents are verified whenever they are stored in caches. However, the current scheme is not practical in practice since its operations incur too much overhead. In this paper, we suggest a simple but effective solution for content verification in NDN.

   @inproceedings{nam2015content,
     title = {Content verification in named data networking},
     author = {Nam, SunWook and Kim, Dohyung and Yeom, Ikjun},
     booktitle = {2015 International Conference on Information Networking (ICOIN)},
     pages = {414--415},
     year = {2015},
     organization = {IEEE}
   }

4. WPC

   Efficient packet routing in highly mobile wireless networks

   Cheoleun Moon, Yusung Kim, Dohyung Kim, and 2 more authors

   Wireless Personal Communications, 2015

   Abs Bib

   Traditional mobile ad-hoc network (MANET) and delay tolerant network (DTN) routing schemes work properly only under the limited assumptions. MANET routing schemes are designed for densely populated networks while DTN routing schemes were developed for dealing with intermittently connected topologies. However, in a real environment, the assumption cannot be hold: the density of nodes constantly changes and a network can be separated due to node mobility even when it is composed of large number of nodes. We propose a routing scheme for maximizing the delivery rate in a network with varying density. In the proposed scheme, data packets are used to search an available path while they are delivered by DTN-based routing. If a path exists, subsequent packets are relayed along the path. Otherwise, packets are delivered continuously using DTN-based routing. Using simulation we show that the proposed scheme achieves high throughput and a low overhead in a dense part of the network, while it outperforms existing DTN routing schemes in an intermittently connected situation.

   @article{moon2015efficient,
     title = {Efficient packet routing in highly mobile wireless networks},
     author = {Moon, Cheoleun and Kim, Yusung and Kim, Dohyung and Yoon, Hyunsoo and Yeom, Ikjun},
     journal = {Wireless Personal Communications},
     volume = {84},
     pages = {1265--1284},
     year = {2015},
     publisher = {Springer}
   }

5. WPC

   An end-to-end rate control protocol for intermittently connected networks

   Euiyul Ko, Dohyung Kim, Hanjin Park, and 2 more authors

   Wireless Personal Communications, 2015

   Abs Bib

   In this study, we propose a rate control algorithm for intermittently connected networks (ICNs), a type of delay/disruption-tolerant network. The different characteristics of ICNs compared with traditional TCP/IP networks lead to problems that do not occur in legacy networks, such as network partitioning, long and varying delays, high loss probability, and asymmetric data transmission rates. To overcome these issues, much recent research has been carried out. However, while the results have helped achieve smooth communication between nodes, there are still certain shortcomings. For example, if many messages are input by the nodes in a network, these schemes do not work well. To resolve this problem, we propose a novel sending rate control algorithm in an additive increase/multiplicative decrease manner. To detect network congestion, we measure the receiving rate, one-way delay, and average number of copies. When the measured receiving rate increases, the congestion window (cwnd) also increases; otherwise, cwnd decreases. The simulations show that the proposed algorithm can adjust the sending rate of nodes to avoid network congestion and provide a fair share of the network for the nodes.

   @article{ko2015end,
     title = {An end-to-end rate control protocol for intermittently connected networks},
     author = {Ko, Euiyul and Kim, Dohyung and Park, Hanjin and Yeom, Ikjun and Seo, Euiseong},
     journal = {Wireless Personal Communications},
     volume = {84},
     pages = {287--303},
     year = {2015},
     publisher = {Springer}
   }

6. IJCS

   End-to-end mobility support in content centric networks

   Do-hyung Kim, Jong-hwan Kim, Yu-sung Kim, and 2 more authors

   International Journal of Communication Systems, 2015

   Abs Bib

   Content-centric networking CCN has been recently proposed as an alternative to traditional IP-based networking. In CCN, content is accessed by content name instead of a host identifier locational identifier. This new type of access methodology rapidly and efficiently disseminates content in combination with the in-network caching mechanism. For practical use of CCN, many network properties studied in IP-based networking are being revisited, and new types of CCN architecture components are being designed. Although mobility is an essential aspect of the future networking system, it has not been sufficiently studied. We therefore address fundamental mobility issues, such as seamless handover, optimal access point selection, network mobility, and handling of persistent interests. In addition, for each issue, we propose practical solutions that efficiently align to a CCN environment. To ensure seamless handoff, we propose various handoff schemes and compare their performance in terms of handoff latency using packet-level simulation. Because our proposed schemes are consistent with the characteristics and rules of CCN, we believe that they can easily be integrated as a part of CCN.

   @article{kim2015end,
     author = {Kim, Do-hyung and Kim, Jong-hwan and Kim, Yu-sung and Yoon, Hyun-soo and Yeom, Ikjun},
     journal = {International Journal of Communication Systems},
     volume = {28},
     number = {6},
     pages = {1151--1167},
     year = {2015},
     publisher = {Wiley Online Library}
   }

2012

1. ICN

   Mobility support in content centric networks

   Do-hyung Kim, Jong-hwan Kim, Yu-sung Kim, and 2 more authors

   In Proceedings of the second edition of the ICN workshop on Information-centric networking, 2012

   Abs Bib

   Content-centric networking (CCN) is designed for efficient dissemination of information. Several architectures are proposed for CCN recently, but mobility issues are not considered sufficiently. We classify traffic types of CCN into real-time and non real-time. We examine mobility problems for each type, and suggest the possible hand-off schemes over CCN. Then, we analyze the delay performance in terms of simulation study. We believe that the proposed schemes can be merged as a part of the CCN easily, since they comply with the inherent nature and rules of the CCN.

   @inproceedings{kim2012mobility,
     author = {Kim, Do-hyung and Kim, Jong-hwan and Kim, Yu-sung and Yoon, Hyun-soo and Yeom, Ikjun},
     booktitle = {Proceedings of the second edition of the ICN workshop on Information-centric networking},
     pages = {13--18},
     year = {2012},
     organization = {ACM},
   }

2011

1. CL

   AQM for weighted fairness in wireless LANs

   Do-hyung Kim, Jong-hwan Kim, Hyun-soo Yoon, and 1 more author

   IEEE Communications Letters, 2011

   Abs Bib PDF

   It is not possible to achieve fairness in IEEE 802.11- based WLANs using only previous fair medium access schemes, because of the impact of higher-layer features such as TCP dynamics and AP congestion. To overcome the limitations of MAC layer approaches, we propose a very simple but effective queue management scheme, which can be applied to the AP. The simulation result shows that the proposed scheme efficiently achieves weighted fairness and can be used to preserve the effect of MAC layer scheduling strategies.

   @article{kim2011aqm,
     title = {AQM for weighted fairness in wireless LANs},
     author = {Kim, Do-hyung and Kim, Jong-hwan and Yoon, Hyun-soo and Yeom, Ikjun},
     journal = {IEEE Communications Letters},
     volume = {15},
     number = {11},
     pages = {1199--1201},
     year = {2011},
     publisher = {IEEE},
   }

2008

1. CFI

   Minimizing the impact of buffer overflow in dtn

   Dohyung Kim, and I Yeom

   In proceedings international conference on future internet technologies (CFI), 2008

   Abs Bib

   In epidemic routing for a DTN, it is well-known that message drop degrades the delivery ratio. To minimize the degradation, we need to protect messages with a small number of copies in a DTN. In this paper, we propose a new drop policy which drops a message with the largest expected number of copies first to minimize the impact of message drop.

   @inproceedings{kim2008minimizing,
     title = {Minimizing the impact of buffer overflow in dtn},
     author = {Kim, Dohyung and Yeom, I},
     booktitle = {proceedings international conference on future internet technologies (CFI)},
     pages = {20},
     year = {2008},
     organization = {Citeseer}
   }