• 한국멀티미디어학회논문지
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• 제20권6호
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• pp.911-917
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• 2017

Tor proxy tool is studied which is most frequently used for ransomeware to penetrate into sensitive information. It will be researched for the malicious methods to spread virus by using Tor and considered a countermeasure to prevent them. We present exit relay methodology for Tor security policy, simulate it, and get a probability to detect the ransomeware. And we compare it with TSS technology which is able to protect the attack via virtual server on exit relay.

• 한국통신학회논문지
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• 제33권11B호
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• pp.1030-1037
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• 2008

본 논문에서는 다중 로봇 (multi-robot)을 활용한 응용분야 중, 미지의 영역에 대한 탐색 (exploration) 능력을 향상시켜서, 주어진 미로 (maze)에서 다중 로봇이 통신을 통해서 협력적으로 출구를 찾아가는 효율적인 방안을 제안하였다. 즉, 미로 형태의 임의의 환경을 생성한 후, 로봇을 무작위로 배치시켜 상호간에 통신을 통하여 출구로 신속히 모두 빠져나오는 문제를 다루고 있다. 미로탐색을 위해 다중 로봇의 지역 탐색에서 사용되었던, 프론티어 셀, 셀 유틸리티등 기존 연구를 활용하였다. 또한 로봇간의 다중홉 무선 통신 (multihop wireless communications)을 위해서 이동성 (mobility)에 강한 일종의 홉기반 (hop-by-hop) 라우팅인, 랜덤 베스킷 볼 라우팅을 채용하였다. 또한, 출구를 찾은 로봇이 일정한 확률에 의거하여 출구 앞에서 정지하거나 혹은, 빠져나가는 의사 결정을 하여, 이 확률적인 결정이 다른 로봇의 행동에 어떻게 영향을 주는지를 실험적으로 조사하였다. 즉, 출구를 찾은 로봇이 현재 위치에서 멈추어서, 통신 중계 지점 (relay)으로 어떻게 활동되어야 최적인지에 대한 문제를 모의 실험을 통해 파악해보았다.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.614-618
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• 2015

This paper described an off-axis head-mounted display system. It is composed of a 7-piece coaxial relay lens group and a freeform surface combiner. This configuration has a simple structure and a wide field of view (FOV). In this design, a freeform surface is chosen as the combiner, to simplify the structure and attain good image quality. We generated this freeform surface by considering both coordinates and normals of discrete data points. Moreover, we realize a coaxial structure in the relay lens group, which is compact and benefits from a loose tolerance requirement. The HMD system we finally realized has a 40° × 30° FOV and 15-mm exit pupil diameter.

• Current Optics and Photonics
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• 제2권3호
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• pp.280-285
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• 2018

A new method to design a see-through off-axis head-mounted-display (OA-HMD) optical system with an ellipsoidal surface is proposed, in which a tilted ellipsoidal surface is used as the combiner, which yields the benefits of easier fabrication and testing compared to a freeform surface. Moreover, we realize a coaxial structure in the relay lens group, which is simple and has looser tolerance requirements, thus making assembly easier. The OA-HMD optical system we realize has a simple structure and consists of a combiner and 7 pieces of coaxial relay lenses. It has a $48^{\circ}{\times}36^{\circ}$ field of view (FOV) and 12-mm exit pupil diameter.

• 한국연극학
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• 제48호
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• pp.485-507
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• 2012

Parodos, the side entrances to orchestra (acting space), was one of the intrinsic elements for the ancient Greek theatre structure. It is worth noting that parodos was the sole structural component that remained the original form while all the other elements such as orchestra, skene, and theatron experienced drastic or gradual changes in form throughout the passage of time. On the reason for parodo's maintenance of the original form, this study suggests a possibility that parodos could be the most intrinsic among the elements for Greek theatre buildings. For evidence, this paper indicates the historical fact that the procession tradition was the key event in the national or civic festival known as City Dionysia, and that the single-direction passageway, as seen in the Panathenaic Way passing through the City Athens, could be the easiest and most efficient way to realize the cause for the procession tradition that is the citizens' participation and subsequent unification. This study suggests another possibility that the single-direction passageway in the procession could be the archetype of parodos. For evidence, this study finds that this type of passageway was ubiquitous around the City Athens especially in the Agora, the most popular place in the city and the gateway to the processional event for Dionysian Cult as well as the space for the earliest Greek theatricality and, therefore, was familiar to the citizens. From the discussion, this paper argues that the Greek theatre should be the miniature of the Agora in terms of form (single-direction passageway) and function (civic participation and unification), and that parodos was the theatrical version of the processional passageway in the Dionysian Cult. In conclusion, this paper argues that parodos played a double role. It satisfied the theatrical necessity by functioning as the passageway to dramatic action (entrance and exit of actor/chorus) and as the literal door for the entrance of the audience members. At the same time, it satisfied the social cause, that is civic participation and subsequent unification, by functioning as the processional passage to relay the theatre space to civic events for the national religious cult.