Frequency-comb-referenced multi-wavelength profilometry for largely stepped surfaces.

Hyun, Sangwon,Choi, Minah,Chun, Byung Jae,Kim, Seungman,Kim, Seung-Woo,Kim, Young-Jin Optical Society of America 2013 Optics express Vol.21 No.8

<P>3-D profiles of discontinuous surfaces patterned with high step structures are measured using four wavelengths generated by phase-locking to the frequency comb of an Er-doped fiber femtosecond laser stabilized to the Rb atomic clock. This frequency-comb-referenced method of multi-wavelength interferometry permits extending the phase non-ambiguity range by a factor of 64,500 while maintaining the sub-wavelength measurement precision of single-wavelength interferometry. Experimental results show a repeatability of 3.13 nm (one-sigma) in measuring step heights of 1800, 500, and 70 μm. The proposed method is accurate enough for the standard calibration of gauge blocks and also fast to be suited for the industrial inspection of microelectronics products.</P>

Interface to Network Security Functions for Cloud-Based Security Services

Hyun, Sangwon,Kim, Jinyong,Kim, Hyoungshick,Jeong, Jaehoon,Hares, Susan,Dunbar, Linda,Farrel, Adrian Institute of Electrical and Electronics Engineers 2018 IEEE communications magazine Vol.56 No.1

<P>Network functions virtualization and cloudbased security services will become increasingly common in enterprise network systems to reduce the system operation costs and take advantage of the diverse network security functions (NSFs) developed by multiple vendors. In such a network environment, standardizing the interfaces to the NSFs of different vendors is essential to simplify the management of these heterogeneous NSFs. In addition, software-defined networking can be imposed to optimize the security service process in such cloud-based service environments by enforcing some types of packet filtering rules at the SDN switches, instead of NSFs possibly placed in remote clouds. The Interface to Network Security Functions (I2NSF) Working Group, which is part of the Internet Engineering Task Force, is currently developing a set of standard interfaces to such heterogeneous NSFs. In this article, we present the design and development of an I2NSF architecture and propose improving its efficiency by integrating it with SDN. In our work, we implement the SDN-integrated I2NSF architecture and its security applications. This article also discusses several standardization and research challenges for I2NSF.</P>

Absolute length measurement with the frequency comb of a femtosecond laser

Hyun, Sangwon,Kim, Young-Jin,Kim, Yunseok,Jin, Jonghan,Kim, Seung-Woo IOP Pub 2009 Measurement Science and Technology Vol.20 No.9

<P>We report exploiting the frequency comb of a femtosecond laser as a means of realizing the time-based SI definition of the meter for length metrology. Specifically, an external-cavity diode laser is continuously tuned to a stabilized frequency comb, and its output frequency is modulated over an extensive range to measure the absolute value of a given length by means of multi-wavelength optical interferometry. This approach could find applications in establishing practical length standards with a small amount of uncertainty directly traceable to time standards.</P>

Design and Analysis of Push Notification-Based Malware on Android

Hyun, Sangwon,Cho, Junsung,Cho, Geumhwan,Kim, Hyoungshick Hindawi Limited 2018 Security and communication networks Vol.2018 No.-

<P>Establishing secret command and control (C&C) channels from attackers is important in malware design. This paper presents design and analysis of malware architecture exploiting push notification services as C&C channels. The key feature of the push notification-based malware design is<I> remote triggering</I>, which allows attackers to trigger and execute their malware by push notifications. The use of push notification services as covert channels makes it difficult to distinguish this type of malware from other normal applications also using the same services. We implemented a backdoor prototype on Android devices as a proof-of-concept of the push notification-based malware and evaluated its stealthiness and feasibility. Our malware implementation effectively evaded the existing malware analysis tools such as 55 antimalware scanners from VirusTotal and SandDroid. In addition, our backdoor implementation successfully cracked about 98% of all the tested unlock secrets (either PINs or unlock patterns) in 5 seconds with only a fraction (less than 0.01%) of the total power consumption of the device. Finally, we proposed several defense strategies to mitigate push notification-based malware by carefully analyzing its attack process. Our defense strategies include filtering subscription requests for push notifications from suspicious applications, providing centralized management and access control of registration tokens of applications, detecting malicious push messages by analyzing message contents and characteristic patterns demonstrated by malicious push messages, and detecting malware by analyzing the behaviors of applications after receiving push messages.</P>

Secure and DoS-Resilient Fragment Authentication in CCN-Based Vehicular Networks

Hyun, Sangwon,Kim, Hyoungshick WILEY INTERSCIENCE 2018 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.2018 No.-

<P>Content-Centric Networking (CCN) is considered as a promising alternative to traditional IP-based networking for vehicle-to-everything communication environments. In general, CCN packets must be fragmented and reassembled based on the Maximum Transmission Unit (MTU) size of the content delivery path. It is thus challenging to securely protect fragmented packets against attackers who intentionally inject malicious fragments to disrupt normal services on CCN-based vehicular networks. This paper presents a new secure content fragmentation method that is resistant to Denial-of-Service (DoS) attacks in CCN-based vehicular networks. Our approach guarantees the authenticity of each fragment through the immediate fragment verification at interim nodes on the routing path. Our experiment results demonstrate that the proposed approach provides much stronger security than the existing approach named FIGOA, without imposing a significant overhead in the process. The proposed method achieves a high immediate verification probability of 98.2% on average, which is 52% higher than that of FIGOA, while requiring only 14% more fragments than FIGOA.</P>

콘텐츠 중심 네트워크를 위한 안전한 패킷 단편화 기술

현상원(Sangwon Hyun) 한국정보보호학회 2017 정보보호학회논문지 Vol.27 No.4

본 논문에서는 콘텐츠 중심 네트워크(CCN, Content-Centric Networking)를 위한 안전한 패킷 단편화(fragmentation) 기술을 제안한다. 제안하는 기술은 패킷조각(fragment)들에 대한 불법적인 위변조 가능성을 차단하고, 패킷조각 수신 시 높은 확률로 즉각적인 신뢰성 검증을 제공함으로써 검증 지연을 악용한 DoS 공격으로부터 높은 안전성을 제공한다. 본 논문의 성능 분석 결과는 약간의 부하 증가만으로 제안하는 기술이 기존 기술보다 훨씬 더 높은 안전성을 제공함을 보여준다. This paper presents a secure and DoS-resistant fragment authentication technique for Content-Centric Networking (CCN). Our approach not only guarantees the authenticity of each fragment, but also provides a high resistance to DoS attacks through the immediate verification of fragment authenticity at interim nodes on the routing path. Our experimental results demonstrate that the proposed approach provides much stronger security than the existing approach, without imposing a significant overhead.

Empirical Modeling and Extraction of Parasitic Resistance in Amorphous Indium–Gallium–Zinc Oxide Thin-Film Transistors

Jun-Hyun Park,Hyun-Kwang Jung,Sungchul Kim,Sangwon Lee,Dong Myong Kim,Dae Hwan Kim IEEE 2011 IEEE transactions on electron devices Vol.58 No.8

<P>We propose an extraction technique for parasitic resistance (<I>RP</I>) with <I>L</I>-, <I>V</I><SUB>GS</SUB>-, and <I>V</I><SUB>DS</SUB>-dependences even for large <I>V</I><SUB>DS</SUB> in amorphous indium-gallium-zinc oxide thin-film transistors (<I>a</I>-IGZO TFTs), by employing <I>I</I><SUB>DS</SUB>-<I>V</I><SUB>GS</SUB> characteristics (as a function of <I>V</I><SUB>DS</SUB> ) of two <I>a</I>-IGZO TFTs with different channel lengths ( <I>L</I><SUB>1</SUB> and <I>L</I><SUB>2</SUB> ). The resistance between the source and drain is modeled as an effective total resistance defined as <I>RT</I><SUP>*</SUP> ≡ <I>V</I><SUB>DS</SUB>/<I>ID</I> for all over the drain bias <I>V</I><SUB>DS</SUB> including both linear and saturation regions. The proposed method can be efficiently employed to model dc <I>I</I>-<I>V</I> characteristics and extract the parasitic resistance in <I>a</I>-IGZO TFTs even with short channel lengths, because the internal drain voltage (<I>V</I><SUB>DS</SUB><SUP>'</SUP>) is accurately calculated as a function of <I>V</I><SUB>GS</SUB>, <I>V</I><SUB>DS</SUB>, and <I>L</I> by deembedding the voltage drop across the parasitic resistance <I>R</I><SUB>P</SUB>.</P>

유전 및 육종 : MS 마커를 이용한 토종닭 브랜드의 유전적 특성 및 개체 식별력 분석

서상원 ( Sangwon Suh ),조창연 ( Chang Yeon Cho ),김재환 ( Jae Hwan Kim ),최성복 ( Seong Bok Choi ),김영신 ( Young Sin Kim ),김현 ( Hyun Kim ),성환후 ( Hwan Hoo Seong ),임현태 ( Hyun Tae Lim ),조재현 ( Jae Hyeon Cho ),고응규 ( Yeo 한국동물자원과학회(구 한국축산학회) 2013 한국축산학회지 Vol.55 No.3

MS 마커는 가축의 유전적 다양성, 유연관계 및 품종식별의 연구에 있어서 매우 유용하다. 본 연구는 26개의 MS 마커를 이용하여 토종닭 브랜드 2집단(우리맛닭, 한협3호)과 토착종 순계 2집단(화이트 레그흔, 로드 아일랜드 레드)을 대상으로 집단내 및 집단간의 유전적 다양성, 계통유전학적 관계, 유전적 균일성 등을 검증하여 고유 유전자원으로서의 가치 구명 및 개체식별력이 높은 마커를 선별하여 토종닭 브랜드 계육의 생산이력시스뎀에 활용 가능한 기초 자료를 제시하고자 실시 하였다. 대립 유전자형 분석결과 총 191개 중 47개(24.6%)가 지단 특이 대립 유전자였으며, 다형성지수의 평균은 HExp=0.667, PIC=0.630으로 산출 되였다. 공시된 320 수 개체에 대한 요인대응분석(FCA) 결과 4개의 군집을 형성하였지만 2개 토종닭 브랜드 집단은 타 집단에 비해 매우 가까운 거리에 위치하고 있었으며, 집단간의 DA 유전거리 결과 또한 이와 동일했다. 각 집단에 대한 유전적 균일도는 모든 집단에서 94% 이상으로 높았다. 이상의 결과는 2개 토종닭 브랜드 집단은 유전적으로 유사하지만 토종닭 순계 집단과는 유전적인 차이가 크며, 순계 2집단 또한 유전적으로 확연히 분리됨을 증명 할 수 있다. 26개 MS마커 사용시 동일개체 출현확률(PI)은 1.17×10-49였다. 2011년 기준으로 닭 사육수수 149,511,309수를 고려해 PI 값이 높은 마커 9~12개 정도를 선별 및 분석에 이용 한다면 동일개체 출현확률(PI)이 1.14×10-15 에서 7.33×10-20 이므로 개체식벽 및 친자 감별이 가능할 것으로 사료된다. 향후 경제적 효율성을 고려하여 MS 마커 및 mtDNA의 SNP를 기반으로 multiplexing PCR 시스템을 확립을 위한 연구가 이행된다면 토종닭 브랜드육의 생산이력시스템에 적용이 가능할 것으로 판단된다. Microsatellite markers have been a useful genetic tool in determining diversity, relationships and individual discrimination studies of livestock. The level of genetic diversity, relationships among two Korean indigenous chicken brand populations (Woorimatdag: WR, Hanhyup3: HH) as well as two pure populations (White Leghorn: WL, Rhode Island Red: RIR) were analyzed, based on 26 MS markers. A total of 191 distinct alleles were observed across the four chicken populations and 47 (24.6%) of these alleles were unique to only one population. The mean HExp and PIC were estimated as 0.667 and 0.630. Nei`s DA genetic distance and factorial correspondence analysis (FCA) showed that the four populations represented four distinct groups. However, the genetic distance between each Korean indigenous chicken brand (WR, HH) and the pure population (WL, RIR) were threefold that among the WR and HH. For the STRUCTURE analyses, the most appropriate number of clusters for modeling the data was determined to be three. The expected probabilities of identity among genotypes of random individuals (PI) were calculated as 1.17×10-49 (ALL 26 markers) and 1.14×10-15, 7.33×10-20(9, 12 with the highest PI value, respectively). The results indicated that the brand chicken breed traceability system employing the own highest PI value 9 to 12 markers, and might be applicable to individual identification of Korean indigenous chicken brand.

시스템 오브 시스템즈의 오류 위치 추정을 위한 통계적 검증 결과 활용 기법 분석

현상원(Sangwon Hyun),신용준(Yong-jun Shin),배두환(Doo-Hwan Bae) 한국정보과학회 2020 정보과학회논문지 Vol.47 No.4

시스템 오브 시스템즈(System-of-Systems, SoS)는 독립적인 이종의 구성시스템들로 이루어진 크고 복잡한 시스템이며, 이런 SoS의 목표 달성도 확인을 위해 통계적 모델 검증(Statistical Model Checking, SMC) 기법이 주로 사용된다. 하지만 SoS가 특정 목표를 달성하지 못하는 경우, SoS내에 존재하는 목표 달성 저해 요소를 효율적으로 찾기 위해 기존 오류 위치 추정 기법을 확장 적용할 수 있다. 하지만, 기존 기법들은 성공, 실패의 테스팅 결과만을 사용하기 때문에, SMC의 확률적 결과값을 기존 위치 추정 기법에 사용하기 위한 추가적인 해석 기법이 필요하다. 따라서 본 연구에서는 SoS에 기존의 오류위치 추정기법을 적용하기 위한 6가지 기법을 소개하고, 재난 대응 SoS를 이용하여 해당 기법들에 대한 비교 분석을 진행하였다. 그 결과, SMC의 결과를 기댓값으로 활용한 기법이 모든 시나리오에서 평균적으로 좋은 성능을 보임을 밝힐 수 있었다. System of Systems (SoS) is a large and complex system comprising independent constituent systems. Statistical Model Checking (SMC) techniques can be used to verify if the SoS achieves its goals or not. However, even if the SoS goal failure is detected using the SMC, finding a root cause of the SoS failure requires more cost than that of a system. One of the candidate solutions for reducing the debugging cost is to apply fault localization techniques on the SoS. However, existing fault localization techniques are designed to utilize testing results of a system. Thus, a method to utilize SMC results is needed to apply existing fault localization techniques to the SoS. In this study, we suggest six utilization methods of SMC results for SoS fault localization, and compare the performance of them on the emergency-response SoS. We found that the method based on the expectation value showed the best performance in the experiment.

시스템 오브 시스템즈의 효율적 검증을 위한 목표 모델 슬라이싱

현상원(Sangwon Hyun),송지영(Jiyoung Song),지은경(Eunkyoung Jee),배두환(Doo-Hwan Bae) 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.12