• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.143-143
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• 2008

Nanowires are promising options for building nanoscale electronic structures coming from high conductivity of nanowires. In particular, Deoxyribonucleic acid (DNA), which is structurally nanowire, can obtain highly ordered electronic components for nanocircuitry and/or nanodevices because of its very flexible length controllability, nanometer-size diameter, about 2 nm, and self-assembling properties. In this work, we used the method to form DNA-Nanowires (NWs) by using chemical treatment on Silicon (Si) surface, and Aminopropyl-triethoxysilane (APTES) was used as inducer of DNA sequence to modify the characteristics of Si surface. Moreover, we performed tilting technique to align DNA by the direction of flow of DNA solution. We investigated the assembly process between DNA molecules and APTES - coated Si surface according to the APTES concentration, from $1.2{\mu}\ell$ to $120{\mu}\ell$. Atomic Force Microscopy (AFM) images showed the combination rate of DNA molecules by the change of APTES concentration. As APTES concentration becomes thicker, aggregation of DNA molecules occurs, and this makes a kind of DNA networks. In this respect, we confirmed that there's a positive relationship between the concentration of APTES and the formation rate of DNA nanowires. Since there have been lots of research preceded to utilize DNA nanowires as template, so by using this positive relationship with proper alignment technique, realization of nano electronic devices with DNA nanowires might be feasible.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.591-593
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• 2016

Device-to-device (D2D) communications underlaid cellular infrastructure is an competitive local area services technology to promote spectrum usage for next generation cellular networks. These potential can only be tap through efficient interference coordination. Previous works only concentrated on interference from D2D pairs whiles interference from CUs to D2D pairs were neglected. This work focus on solving uplink interference problem emanating from multiple CUs sharing its resource with multiple D2D pairs. The base station (BS) acting as a supervisor selfishly institute a pricing scheme to manage the interference it experience from D2D pairs based on its Quality of service (QoS) requirement. D2D pairs following the supervisor make power allocation decisions considering the price from the BS in a non-cooperative game fashion. In order for the D2D pairs to also meet their QoS requirement, they suggest a price to the BS called discount price which reflects the interference they receive from the CUs. Finally, we analyze the proposed approach.

• Annual Conference of KIPS
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• 2002.11b
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• pp.1595-1598
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• 2002

네트워크 장애로 인한 인터넷 서비스 품질의 저하는 사용자와 서비스 제공자에게 여러 가지 형태로 손실을 가져오므로 망의 우회경로 설정 및 복구방안은 중요한 요소가 되고 있다. 망 복구에 있어서 중요한 과제는 작업 경로(working path)에 대한 복구 경로(restoration path)를 설정하는 것이다. 장애가 발생하더라도 서비스의 중단이 없도록 하기 위해서는 복구 경로를 설정할 때 작업 경로의 대역을 보장할 수 있는 복구 경로를 실정해야 한다. 이를 위해 MPLS망에서는 명시적 Routing기법에 기반을 둔 Constraint-based routing이 제안되었고 또한 망의 경로 복구를 위해 정적 및 동적설정기법이 제안되고 있다. 본 논문에서 제안된 방식은 확장된 OSPF 프로토콜의 TE-LSAs를 이용하여 또 다른 virtual 망을 구성하고 기본경로 중간의 TE-LSR을 새로운 PIL로 설정하여 빠른 대체 LSP를 설정 및 복구하는 기법을 성능 비교를 통해 망 자원의 효율적 사용을 보고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.361-364
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• 2014

무선 센서 네트워크를 구성하는 각 센서 노드들은 한정된 전력의 배터리로 동작하므로, 센서 네트워크에서의 에너지 효율성은 중요한 이슈이다. 따라서, 센서 노드의 에너지 소모를 줄여서 전체 네트워크 수명을 최대화하기 위해 MAC 계층에서의 다양한 프로토콜이 제안되었다. 본 논문에서는 센서 네트워크의 에너지 효율성을 향상시키기 위한 에너지 효율적인 CA-MAC(Context Adaptive MAC) 프로토콜을 제안한다. 제안된 CA-MAC 프로토콜은 데이터의 전송 여부를 결정하는 각 버퍼 임계값을 싱크와 노드의 거리에 따라 차등적으로 설정함으로써 노드의 에너지 소비를 감소시켜 전체 네트워크의 에너지 효율성을 크게 향상 시킨다. 또한, 전송 지연 시간을 감소시키기 위하여 센싱된 데이터의 긴급 여부에 따른 전송을 수행한다. 본 논문의 성능 평가는 OMNeT++을 이용한 모의실험을 통해 진행하였으며, 그 결과 기존에 제안되었던 S-MAC 및 T-MAC 프로토콜과 비교하여 제안된 기법이 데이터 전송 시간과 에너지 효율성을 향상시키고 네트워크 수명을 연장하였음을 확인하였다.

• ETRI Journal
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• v.31 no.2
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• pp.182-192
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• 2009

Rain attenuation and intercell interference are two crucial factors in the performance of broadband wireless access networks such as local multipoint distribution systems (LMDS) operating at frequencies above 20 GHz. Power control can enhance the performance of downlink CDMA-based LMDS systems by reducing intercell interference under clear sky conditions; however, it may damage system performance under rainy conditions. To ensure robust operation under both clear sky and rainy conditions, we propose a novel power-control scheme which applies an adaptive neuro-fuzzy inference system (ANFIS) for downlink CDMA-based LMDS systems. In the proposed system, the rain rate and the number of users are two inputs of the fuzzy inference system, and output is defined as channel quality, which is applied in the power control scheme to adjust the power control region. Moreover, ITU-R P.530 is employed to estimate the rain attenuation. The influence of the rain rate and the number of users on the distance-based power control (DBPC) scheme is included in the simulation model as the training database. Simulation results indicate that the proposed scheme improves the throughput of the DBPC scheme.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.6-11
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• 2020

In today's world, the design industry is becoming more complex, with the development of networks such as the internet and revolutionary changes in information and telecommunications. As the demand for designers to cope with various situations occurring in these industrial sites or solve problems in practice promptly is required, a capstone design program was developed in collaboration with the industry. Capstone design classes have positive effects on creative problem solving ability, academic achievement and learning satisfaction by allowing students to think and experience the practical problems of the industrial field. It is also effective in improving communication, creative thinking and critical thinking. The purpose of this study is to search for talent training methods needed in the fashion industry and to develop effective programs through capstone design class studies conducted in the fourth grade of fashion design majors from 2017 to 2019 (6 semesters). Through these studies, the aim is to search for talent training methods needed in the fashion industry and to develop effective programs. If the capstone design learning method is used as a method of solving problems through close communication between the company and the educational field as an industry-academia cooperation system, it is expected to be positioned as a field-type human resource education method that is required in the industrial field.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.1-8
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• 2009

The proposed real-time structural health monitoring(SHM) system in past transferred and received data, central server gathered data from sensors, through coaxial cable. an immense sum of money is required to structure sensor network using coaxial cable. This paper proposes USN-based structural health monitoring(SHM). AIso, this paper designs and realizes prototypes according to proposed SHM. The value of sensing data obtained through HSDPA transfer to the BMS(Bridge Monitoring Server) passing through the TCP / IP socket by building two-way communication system, We have implemented a complete graph converting full system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.239-243
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• 2011

In wireless ad-hoc network, the detection of link breakage and re-establishing the route path causes lots of network overhead and results in communication delay. In the LBN method, the node causing a link breakage actively sends a message to neighbors so that they can instantly start re-establishing process of new path. In this paper we describe the result of network simulation we performed using NS2 to show the effectiveness of LBN method.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.678-685
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• 2016

The standard high-availability seamless redundancy (HSR) protocol utilizes duplicated frame copies of each sent frame for zero fail over time. This means that even in cases of a node or link failure, the destination node will receive at least one copy of the sent frame, resulting in no network downtime. However, the standard HSR is mostly based on the electrical signal connection inside the node, which leads to the production of considerable latency at each node due to frame processing. Therefore, in a large scale HSR ring network, the accumulated latencies become significant and can often restrict the mission-critical real-time application of HSR. In this paper, we present a novel design for optical HSR (OHSR) that uses beam splitting/combining techniques. The proposed OHSR passes the frames directly to adjacent nodes without frame processing at each node, thereby theoretically generating no latency in any node. Various simulations for network samples, made to validate the OHSR design and its performance, show that the OHSR outperforms the standard HSR.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.704-715
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• 2016

In this paper, we explore a low-complex bandwidth allocation (BA) scheme with multi-level service guarantees in VLC-OFDM systems. Effective capacity theory, which evaluates wireless channel capacity from a novel view, is utilized to model the system capacity under delay QoS constraints of the link layer. Since intensity modulation of light is used in the system, problems caused by frequency selectivity can be neglected. Then, the BA problem can be formulated as an integer programming problem and it is further relaxed and transformed into a concave one. Lagrangian formulation is used to reformulate the concave problem. Considering the inefficiency of traditional gradient-based schemes and the demand for distributed implementation in local area networks, we localize the global parameters and propose a quasi-distributed quadratic allocation algorithm to provide two-level service guarantees, the first level is QoS oriented, and the second level is QoE oriented. Simulations have shown the efficient performance of the proposed algorithm. The users with more stringent QoS requirements require more subcarriers to guarantee their statistical delay QoS requirements. We also analyze the effect of subcarrier granularity on the aggregate effective capacity via simulations.