Earticle

스마트폰, PC나 태블릿과 같은 스마트 단말 플랫폼들이 대중들에게 확산되면서, 스마트 TV역시 이 추세에 편승하려고 한다. 시장 규모도 신속히 커지고 있다. 대한민국 스마트 TV 시장은 전 세계적으로 높은 보급률을 가지고 있는 반면, 그 만큼 보안요소와 해킹 위험 요소가 따르고 있다. 본 논문은 여러 가지 스마트 TV의 해킹 사례와 공격 가능성을 제시하여 취약점 분석 및 대응 방안에 대해 분석하였다. 삼성전자나, LG등 대부분 스마트 TV의 운영체제가 리눅스 기반으로 최근 해킹 사례도 리눅스 해킹 기법과 유사하다. 대부분 리눅스 OS를 기반으로 샌드박스를 탑재해 보안을 강화 했지만 프록시를 이용해 우회기법을 사용하거나 APT 공격이나 역공학으로 완성된 앱을 소스코드로 변환해 악성코드를 삽입 후 앱 스토어에 등록하는 등 현재 해킹 사례는 늘어가고 있다. 그리고 앞으로 새로운 해킹 기법과 다양한 방법들이 생길 것이다. 본 논문으로 발전해나가는 스마트 TV의 보안 위협을 인지하고 앞으로 새로운 해킹으로 인한 대비책을 세우고 준비하는 효과를 기대한다.

Smart-phone, PC or tablet platforms, such as smart terminals spread to the masses trying to capitalize. Smart TV also is increasing. In Korea, market size of TV is growing fast with growth of risk of hacking. In this paper, several kinds of Smart TV hacking cases are presented with the possibility of attacks against the vulnerability analysis and countermeasures. Most of the Linux operating system is open. Thus, it is vulnerable for latest hacking techniques. Most are based on the Linux OS to enhance security mount Sand-Box. However, bypass procedure using the technique, or APT attacks can avoid San-Box technique. New hacking techniques and a variety of ways will occur in the future. Therefore, this paper will develop Smart TV, and it analysis of a security threat and establishes better prepared in the future because new hacking attacks are expected to prepare more.

Mobile end users cannot utilize high upload bandwidths that are available in wireless access networks since wireless link based packet losses degrade TCP performance dramatically. We propose a TCP performance enhancing proxy pair called PROPER that detect packet losses earlier and prevent TCP performance degradation. PROPER is transparent to TCP and requires no modifications on neither TCP sender nor receiver. PROPER works in harmony with various TCP variants like CUBIC and BBR. Netem based performance and fairness emulation tests show that PROPER prevents TCP performance degradation on wireless access networks besides it can safely coexist with regular TCP traffic.

In this article we review the ID Based Proxy-Blind signature scheme proposed by Zhang et al. and we give an attack on the scheme revealing the master secret key used in the construction of their scheme.

본 연구는 DDoS(Distributed Denial of Service, 분산 서비스 거부) 공격에 대하여 기존의 방어 전략의 한계가 드러나 고 있는 시점에서, 공격력을 감소시키고 공격대상을 분산시키는 DDoS 공격 방어 구축 방안을 제시하였다. 현재 DDoS 공격은 개인·기업·연구소·대학·주요 포털 사이트·금융기관 등으로 그 목표와 범위가 광범위해지는 특징을 지니고 있다. 또한 공격 양상도 네트워크 대역인 Layer 3를 소진하는 공격기법에서 웹 어플리케이션인 Layer 7을 주목 표로 공격이 변화하고 있다. 이러한 DDoS 공격에 대하여 Proxy Server Group과 Dynamic DNS를 이용한 DDoS 공격을 효율적으로 분산·감소시 키기 위한 구축방안을 제시하였다.

As the existing strategy of preventing DDoS(Distributed Denial of Service) attacks has limitations, this study is i ntended to suggest the more effective method of preventing DDoS attacks which reduces attack power and distribut es attack targets. Currently, DDoS attacks have a wide range of targets such as individuals, businesses, labs, universities, major po rtal sites and financial institutions. In addition, types of attacks change from exhausting layer 3, network band to pri marily targeting layer 7. In response to DDoS attacks, this study suggests how to distribute and decrease DDoS threats effectively and effi ciently using Proxy Server Group and Dynamic DNS.

본 연구는 최근 들어 DDoS 공격이 단순히 서비스를 방해하는 것에서 벗어나, 다양한 공격 기법을 혼합한 멀티 벡터(Multi-Vector) 공격으로 발전하고 있다. 이러한 멀티벡터 공격은 DDoS 공격과 더불어 악성코드를 감염시켜, 내부 정보 유출 및 좀비PC를 만들어 DDo S 공격용에 활용될 경우에는 기존의 DDoS 공격 및 악성코드 감염에 대한 방어 전략으로는 한계점이 있다. 따라서 본 논문에서는 다양한 방법을 이용한 멀티벡터 공격을 효과적으로 방어하기 위한 Reverse Proxy Grou p과 PMS(Patch Management Server)를 제시하고자 한다.

The objective of DDoS Attacks is to simply disturb the services. In recent years, the DDoS attacks have been ev olved into Multi-Vector Attacks which use diversified and mixed attacking techniques. Multi-Vector Attacks start from DDoS Attack and Malware Infection, obtain inside information, and make zombie PC to reuse for the next DDoS attacks. These forms of Multi-Vector Attacks are unable to be prevented by the exi sting security strategies for DDoS Attacks and Malware Infection. This paper presents an approach to effectively defend against diversified Multi-Vector attacks by using Reverse Proxy Group and PMS(Patch Management Server).

본 논문에서는 mobile WiMAX 네트워크에서 PMIPv6를 이용하여 네트워크-계층 이동성을 제공하는 경우, 핸드오버 성능 향상을 위한 proxy 기반의 고속 핸드오버를 제안하였다. 이를 위해 3개의 링크-계층 메시지와 1개의 네트워크-계층 메시지를 새롭게 정의하였으며, 이를 이용하여 링크 핸드오버 수행시 미리 바인딩 절차를 수행함으로써 핸드오버 지연시간을 줄이고, 패킷 손실과 패킷 순서 어긋남 문제를 고려한 버퍼링 메커니즘을 제안하였다. 그리고 성능 분석을 통해 제안한 방식이 PMIPv6와 비교하여 더 우수한 성능을 나타냄을 확인하였다.

In this paper, we propose a proxy-based fast handover scheme to improve a performance in the mobile WiMAX network using PMIPv6 for supporting the network-layer mobility. In our proposed scheme, we define three link-layer messages and one network-layer message to reduce the handover latency, and propose a buffering mechanism to minimize packet loss and solve out-of-sequence problem. A performance evaluation indicates that the proposed scheme works more efficiently than PMIPv6 in terms of the handover latency and packet loss.

현재 무선 환경에서 이동성을 제공하려는 노력은 다양한 계층의 프로토콜에서 활발히 진행이 되고 있으 며 이중에서도 IP 서브넷이 변경 되어도 이동성이 제공 가능한 IP 이동성 기술이 다양한 계층의 이동성 프로토콜 중에서도 가장 활발히 연구가 이루어지고 있다. IP 이동성 기술은 Mobile IP(MIP)가 나온 이후에 핸드오버 지연을 개선한 Hierarchical MIP 및 Fast MIP 등 다양한 타입으로 확장되어 연구가 진행 중에 있다. 그러나 MIP의 경우는 단말에 MIP Client 스택이 탑재 되어야 하고 단말의 전력 소모 및 HO 지연 크다는 단점 등으로 인하여 기술이 활성화되는데 한계성을 지녀 왔다. 따라서 최근에는 이를 개선한 Proxy MIP 관련 연구들이 활발히 이루어지고 있으며 또한 IP 계층 이동성 기술만으로는 성능 개선에 한계가 있다고 보고 다양한 계층의 이동성 기술과 연동을 하려는 시도도 동시에 이루어지고 있다. 따라서 본 논문에서는 타 계층에서 제공되는 MIH 프로토콜 기능을 활용하여 802.11WLANs 환경에 Proxy MIPv4를 적용하여 이동성을 제공 시 발생하는 핸드오버 지연 요소를 최소화 하였다. 제안된 메커니즘은 MIH가 제공하는 Event, Command, Information 서비스를 활용하여 단말이 새로운 Target 망에 접속하기 이전에 인증 Key 교환 기법을 통해 핸드오버 시 발생하는 인증 지연을 최소화하였으며 추가적으로 Inter-AP간 Tunneling 및 Forwarding 기법을 적용하여 핸드오버 시 발생되는 Packet 손실을 최소화 하는 성능 향상 방안을 제안하였다

Recently, there are many efforts to support seamless mobility in 802.11 WLANs using IP Layer mobility protocols. The IP layer mobility protocols are the most efficient mechanism to guarantee the service session continuity when IP subnet is changed during handover. Even if the IP layer mobility protocols are quite efficient, the feature of the protocols that had been designed to consider only L3 layer makes it difficult to improve the performance of handover more and more. Nowadays, to overcome this limitation of IP mobility protocols, many researchers have worked on the mobility protocols integration of different layers (e.g., L2 layer). In this paper, we propose the enhanced Proxy MIPv4 to minimize the latency of handover using MIH protocol in 802.11 WLANs. The proposed mechanism minimizes the latency of authentication by exchanging security keys between Access Routers during handover. Moreover, it also minimizes packet losses by Inter-AP Tunneling and data forwarding.

현재 코로나-19 팬데믹 현상으로 인해 기업이나 기관에서는 원격근무를 제공하는 상황에서 안전한 근무환경을 구축 하기 위해 논리적 망 분리 기술 중 하나인 가상화 데스크톱 기술을 도입하고 있다. 가상화 데스크톱 기술을 도입함에 따라 기업이나 기관에서는 망분리 환경을 보다 안전하고 효과적으로 운영할 수 있게 되었으며, 업무망에 신속하고 안전 하게 접근해 업무 효율성과 생산성을 높일 수 있게 되었다. 그러나 가상화 데스크톱 기술을 도입함에 있어, 높은 사양의 서버와 스토리지, 라이선스의 비용적인 문제가 있으며, 운용 및 관리적인 측면에서의 보완이 필요한 실정이다. 이에 대 응하기 위한 방안으로 기업이나 기관에서는 클라우드 컴퓨팅 기반의 기술인 가상 데스크톱 서비스(DaaS, Desktop as a Service)로 전환하는 추세이다. 하지만 클라우드 컴퓨팅 기반의 기술인 가상 데스크톱 서비스에서 공동책임모델은 사용 자 접근 통제와 데이터 보안은 사용자에게 책임이 있다. 이에 본 논문에서는 가상 데스크톱 서비스 환경에서 공동책임 모델을 근거로, 사용자 접근 통제와 데이터 보안에 대한 개선 방안으로 클라우드 기반 하드웨어 보안 모듈(CloudHSM) 과 edge-DRM Proxy를 제안한다.

Due to the current COVID-19 pandemic, companies and institutions are introducing virtual desktop technology, one of the logical network separation technologies, to establish a safe working environment in a situation where remote work is provided. With the introduction of virtual desktop technology, companies and institutions can operate the network separation environment more safely and effectively, and can access the business network quickly and safely to increase work efficiency and productivity. However, when introducing virtual desktop technology, there is a cost problem of high-spec server, storage, and license, and it is necessary to supplement in terms of operation and management. As a countermeasure to this, companies and institutions are shifting to cloud computing-based technology, virtual desktop service (DaaS, Desktop as a Service). However, in the virtual desktop service, which is a cloud computing-based technology, the shared responsibility model is responsible for user access control and data security. In this paper, based on the shared responsibility model in the virtual desktop service environment, we propose a cloud-based hardware security module (Cloud HSM) and edge-DRM proxy as an improvement method for user access control and data security.

The objective of the household livelihood determination using PMT methodology is to use variables that can represent household income in situations where there is no data, methods and methodology to directly determine household income and evaluate household livelihood and on the outcome determine target group in need for social welfare assistances and create nationwide electronic database of the target groups The database created using this methodology can be used in policy development, determination of target groups of certain social assistances and services, implementation of appropriate policies of determination of form and amount of assistances and services

Modern cloud applications often operate as unmodified third-party services or legacy code, where direct instrumentation for observability is infeasible. This paper investigates whether a minimal black-box observability pipeline can still provide actionable insights in such contexts. We compose a standard stack—Envoy proxy, OpenTelemetry Collector, Prometheus, Jaeger, and Grafana—to collect metrics and traces without modifying application code, and we apply it to two representative workloads: a lightweight demo service and the OWASP Juice Shop. Our evaluation shows that proxy-only instrumentation captures meaningful demand and latency signals, that exported spans faithfully reflect traffic bursts visible in proxy metrics, and that distributed traces reveal endto- end error paths (e.g., 404 failures). These findings indicate that a carefully orchestrated open-source stack can approximate the diagnostic value of white-box instrumentation. The contributions of this work are a reproducible pipeline design and an empirical assessment demonstrating how such a configuration can reduce mean-time-to-detect (MTTD) failures and support service-level objective monitoring under synthetic load scenarios.

Web Services offer many benefits over other types of middleware in distributed computing. However, usage of Web Services results in large network bandwidth since Web Services use XML-based protocol which is heavier than binary protocols. Even though there have been many researches to minimize the network traffic and bandwidth usages of Web Services messages, none of them are solving the problem clearly yet. In this paper, we propose a transparent proxy with cache to avoid transfer of repeated SOAP data, sent by Web Service to an application. To maintain the cache consistency, we introduce publish/subscribe paradigm using WS-Eventing between the proxy and Web Service. The implemented system based on our proposed architecture will not compromise the standards of Web Service. The evaluation of our system shows that caching SOAP messages not only reduces the network traffic but also decreases the request delays.

This study empirically investigates whether low-frequency liquidity proxies that are popular among researchers capture liquidity effectively and, if they do, which of the proxies measures liquidity best in emerging markets. We carry out a comprehensive analysis using a tick data that covers 1,183 stocks from 21 emerging markets. The use of a tick data allows us to compare various low-frequency liquidity proxies with a range of high-frequency transaction cost and price impact measures. We have several important findings. We find rich dispersion in transaction costs and price impacts across emerging markets. We also find that most of the spread proxies including Roll’s spread, LOT, and Zeros perform relatively well in emerging markets. But when the effectiveness is defined as how accurately a proxy measures actual transaction costs, LOT is most effective in the majority of the emerging markets considered in our study. When it comes to price impact proxies, the Amihud measure is clearly the most effective one with Amivest being the close second. Furthermore, certain firm and market characteristics such as turnover, return volatility, firm size, investibiity, legal origin, and trading mechanism significantly affect how accurately a proxy measures liquidity. Finally, it is important to recognize that there is no one universal proxy that captures liquidity best across different emerging markets. One that works best in most of the markets does not necessarily performs best in a specific market. Hence, it is important to know which proxy is the best liquidity proxy in a specific emerging market. In this regards, the results presented in this paper can be useful when one opts to identify the most efficient liquidity proxy in a specific emerging market.

among researchers capture liquidity effectively and, if they do, which of the proxies measures liquidity best. We carry out a comprehensive analysis using tick data that covers 1,183 stocks from 21 emerging markets. The use of tick data allows us to compare various low-frequency liquidity proxies with various high-frequency transaction cost and price impact measures. We have several important findings. We find rich dispersion in transaction costs and price impacts across emerging markets. We also find that most of the spread proxies, including Roll’s spread, LOT, and Zeros, perform relatively well in emerging markets. But when it comes to price impact proxies, the Amihud measure is clearly the most effective. Finally, it is important to recognize that there is no one universal proxy that captures liquidity best across different emerging markets. One that works best in most of the markets does not necessarily perform best in a specific market. Hence, it is important to know which proxy is the best liquidity proxy in a specific emerging market. Finally, it appears that there are some countries where none of the proxies can be reliably employed.

The intestinal microbiota, an invisible organ supporting a host’s survival, has essential roles in metabolism, immunity, growth, and development. Due to the influence of the intestinal microbiota on the biology of an organism, application of such data to wildlife conservation has gained interest. While there is a standard protocol for studying the human intestinal microbiota, an equivalent one for wildlife is still under development. A major challenge is sampling the intestinal microbiota in an effective, unbiased way. Faecal samples are a popular proxy of the intestinal microbiota because collection is non-invasive, convenient, and allows for longitudinal sampling. Yet, it is unclear whether the faecal microbiota is representative of the intestinal microbiota. In amphibians, research on sampling methodology is limited. In this study, we first characterise and compare microbiota (small intestine, large intestine, faeces) of two Hong Kong stream-dwelling frog species: the Lesser Spiny Frog (Quasipaa exilispinosa) and the Hong Kong Cascade Frog (Amolops hongkongensis). We found that both species have similar dominant phyla and families, but diverge in terms of the dominant genera. Second, we assess the performance of faecal microbiota in representing the intestinal microbiota in these two species. By comparing the microbiota between three sample types (small intestine, large intestine, and faeces), we found (1) that microbiota of small and large intestine differs significantly, (2) that faeces are not an appropriate proxy of both intestinal sections, and (3) a set of microbial taxa that significantly differ between sample type. Our study raises caution on equating faecal and intestinal microbiota. The use of faeces can avoid sacrifice an animal, but researchers should avoid over-extrapolation and interpret results carefully.

This study examines whether firms’ decisions to offer company stock in defined contribution (DC) plans are explained by managers’ corporate control motives. Using a large sample of proxy voting outcomes, I find that employee ownership in DC plans is significantly and positively associated with the level of voting support for management sponsored proposals. This suggests that managers encourage employee DC holdings in company stock in order to receive higher voting support in favor of management. The effects of employee ownership on voting outcomes are significantly greater in subsample tests than in full sample tests: management proposals opposed by Institutional Shareholder Services, management proposals of close votes, director election votes receiving more than 20% of votes withheld, and say-on-pay frequency proposals.

연구목적: 본 연구의 목적은 초기 성인기 발달장애인(지적장애인 및 자폐성장애인)의 삶의 질 전체, 하위요인 및 지표별 수준을 파악하고, 본인, 교사 및 부모 세 집단 평정의 차이를 비교 및 분석하는 것이다. 연구방법: 본 연구는 박승희 외(2019)가 개발한 ‘한국 발달장애성인의 삶의 질 척도(QLS- KADD)’를 발달장애성인이 응답하기에 적합한 ‘자기보고용’으로 연구절차를 통해 수정하여 발달장애인이 자신의 삶의 질을 처음으로 직접 평정한 자료를 사용했다. ‘QLS- KADD: 자기보고용’을 사용하여 발달장애인 본인에게 수합한 자료 47부와 원도구를 사용하여 교사와 부모에게 수합한 자료 각각 47부를 합해, 총 141부 응답을 분석했다. 연구결과: 발달장애인 본인이 평정한 전체 삶의 질과 4가지 하위요인 수준은 4점 척도의 3점대(그렇다) 초반으로 나타났다. 전체 삶의 질과 4가지 하위요인 수준 모두에서 본인, 교사 및 부모 세 집단의 평정에 유의한 차이가 있었으며, 삶의 질 32개 지표 중 30개 지표에서 집단 간 유의한 차이를 나타냈다. 결론: 본 연구는 삶의 질 측정에서 신뢰로운 원 도구의 ‘자기보고용’을 사용해 삶의 질에 대해 본인응답 자료를 일대일 조사로 수합하여 분석하고, 자기보고용 척도의 삶의 질 지표 32개를 제시한 의의가 있으며, ‘본인’ 뿐 아니라 주변인인 ‘교사’와 ‘부모’의 평정 자료를 함께 수집하여 세 집단 평정 사이의 일치와 차이를 분석하고 그 차이에 대한 논의를 진전시킨 것에 의의가 있다. 발달장애인 본인 응답 자료의 중요성과 자기보고용 도구의 개발과 동시에 응답의 타당도와 신뢰도 증진을 위한 과제들에 관심을 촉구하며 후속연구를 제안하였다.

Purpose: The purpose of this study is to measure the quality of life of early adulthood individuals with developmental disabilities(DD) and to compare and analyze the differences in the self-reports, teacher and parent proxy reports. Method: The study utilized data collected through a modified version of the "Quality of Life Scale for Korean Adults with Developmental Disabilities(QLS-KADD)," originally developed by Park et al.(2019). The modified scale was tailored for self-reporting by individuals with DD. Data were collected from 47 self-reports, 47 teacher reports, and 47 parent reports, totaling 141 responses. Results: The overall quality of life and 4-factors rated by early adulthood individuals with DD were in the positive range, scoring in the 3-point range(agree) in the 4-point likert scale. Significant differences were observed in the ratings among the three groups (self, teachers, and parents) for both the levels of overall quality of life and the 4-factors. Out of 32 life quality indicators, significant differences among groups were found in 30 indicators. Conclusion: This study holds significance in being the first to analyze a data set on the quality of life involving the proxy reports and self-reports by individuals with DD, considering their subjective perspectives in measuring quality of life. The study emphasizes the importance of developing self-report tools for individuals with DD and highlights the challenges and tasks for enhancing the validity and reliability of their responses.