Earticle

무선센서네트워크(WSN)는 다양한 환경에서 정보수집을 목적으로 하는 응용분야에 널리 사용된다. WSN을 구성하는 센서노드는 저 전력 배터리를 기반으로 동작하므로 이를 고려한 WSN 수명연장은 중요한 연구목표이다. 본 논문은 효율적인 WSN을 구성하기 위해 노드의 에너지 소비는 적으면서도 클러스터 부하 균등화를 이룰 수 있는 최적화된 클러스터링 프로토콜을 제시한다. 프로토콜의 핵심 아이디어는 센서노드가 저장할 수 있는 정보용량의 한 계치를 이용해서 클러스터 멤버노드와 클러스터 밀집도가 균등분포(load balancing)되도록 하는 것이다. 또한 최적 클 러스터 헤드 확률모델을 도입해서 WSN을 분할하는 클러스터가 최적화 되도록 한다. 이를 통해서 네트워크 부하의 적절한 분산과 에너지 소비 효율을 극대화하는 성능개선을 이끌어 낼 수 있다. 성능평가 결과 제안하는 프로토콜은 대표적인 계층형 프로토콜인 LEACH와 최근에 제안된 클러스터 기반 지역 멀티 홉 라우팅 프로토콜(CBLM)보다 더 수명이 연장되고 안정화 될 수 있었다.

The Wireless sensor network(WSN) consisting of a large number of sensors aims to gather data in a variety of environments. The sensor nodes operate on battery of limited power. so, To extend network life time is major goals of research in the WSN. In this paper, we state the key point of a energy consumption with minimum&load balancing. The proposed protocol guarantee balance of number of cluster member nodes using the node memory threshold and optimization of distribution of cluster head using the optimized clustering method. The results show that the proposed protocol could support the load balancing and high energy efficiency by distributing the clusters with a reasonable number of member nodes. The simulation results show that our schme ensure longer life time in WSN as compare with existing schemes such as LEACH and CBLM.

본 논문에서는 네트워크 상황 정보를 이용한 다중 인터페이스 단말의 배터리 수명 연장 방법을 제안한다. 단말은 현재 접속 네트워크에 병목현상이 발생하는 경우, 다중 인터페이스를 이용하여 다중 경로로 데이터를 수신한다. 하지만 다중 인터페이스를 이용하는 경우 단말의 배터리 소모가 많아 단말의 배터리 수명이 짧아진다. 이러한 배터리 소모를 줄이기 위해 OLT를 통해 네트워크의 병목현상 유무를 판단하고 단말에게 네트워크 상황 정보를 전송한다. 단말은 네트워크 상황 정보를 통해 하나의 인터페이스를 비활성화 시켜 에너지 소비를 절감시킨다. 단일 인터페이스와 다중 인터페이스를 사용함에 따른 배터리 소비량을 계산하여 제안 방안의 효과를 확인하였다.

In this paper, we propose the battery life time extension method in the multi-interface terminal by using the state information in an optical wireless integrated network architecture. When the bottlenecks occurs in the network, the terminal receives data packets via multipath. However, the battery life time is rapidly reduced because the power consumption of the terminal is bigger than single interface. For reducing the power consumption in the multi-interface terminal, the Optical Line Terminal (OLT) confirms whether the bottleneck phenomenon is occurred or not. And the network state information is transmitted to the terminal. The terminal turns one of the interfaces off to reduce the power consumption. In order to estimate the performance, we compare the power consumption between single and dual interfaces.

In this paper, we’re compared network protocol which is network lifetime longer when using LEACH Protocol, SEP, and TEEN in a heterogeneous Wireless Sensor Network with a Large Sensor Area. Also, we propose a method of divided layer the wide-area sensor filed and transmitting a multi-hop to improve the network lifetime. And we’re compared network protocol which is network lifetime more improved apply the proposed method to LEACH Protocol, SEP, and TEEN. We tried to compare results, TEEN showed the best network lifetime. Apply the proposed method to divided the sensor field, L-TEEN (Layered TEEN)’s network lifetime rates of improvement is highest.

In this paper, we’re compared network protocol which is network lifetime longer when using LEACH Protocol, SEP, and TEEN in a heterogeneous Wireless Sensor Network with a Large Sensor Area. Also, we propose a method of divided layer the wide-area sensor filed and transmitting a multi-hop to improve the network lifetime. And we’re compared network protocol which is network lifetime more improved apply the proposed method to LEACH Protocol, SEP, and TEEN. We tried to compare results, TEEN showed the best network lifetime. Apply the proposed method to divided the sensor field, L-TEEN (Layered TEEN)’s network lifetime rates of improvement is highest.

In wireless sensor networks, the methods for both data collection and data transmission to base station are important factors for sensor node energy consumption. We can transmit the data generated by each node more efficiently using clustering. One of the clustering methods, self-organization clustering, cannot guarantee homogeneous head-node selection. We suggest the adjusted-TTC method, which improves the capacity of the TTC to select a head-node evenly and efficiently in the network field through 2-tier clustering. Adjusted-TTC prioritizes a head-node at the first stage by removing head-nodes that are too close to the other head-nodes in the network field. This improves the data transmission energy efficiency among sensor nodes by reducing the number of non-receiving advertisement messages.

The key challenge while designing any wireless sensor network is to elevate the life time of network. To maximize network lifetime many factors are taken into consideration, such as reduction in power usage, selection of optimized route thus making it economically efficient accompanied with use of improved version of communication models & advanced sets of instruction i.e. protocols. To avoid abbreviation of power in nodes, residual power is forwarded to every node. Formulation of congestion zone called bottle neck is controlled by cope algorithm comprising a combination of both duty cycle and network coding thus reduces loss of data. As a result network lifetime is increased by reducing node count and path count near the sink node. This results in abundant data transmission near the sink with same number of transmission, thus increasing efficiency of system with increased lifetime. The other two prime factor taken into consideration are the amount of packet delivered as well as its latency.

무선 센서 네트워크에서도 다른 네트워크와 마찬가지로 시간 관계를 유지하는 것이 중요하므로, 무선 센서 네트워크의 특성을 고려한 시각 동기화 프로토콜인 IBS(Indirect-Broadcast Synchronization)가 2012년에 개발되었다. IBS는 클러스터 트리 형태에서 동작하므로 일반 노드보다 더 많은 에너지를 소모하는 클러스터 헤더에 의해서 주로 네트워크 전체 수명이 좌우될 수 있다. 이 논문에서는 클러스터 트리를 부분적으로 재구성함으로써 전체 에너지 소모를 줄이고 네트워크 수명을 연장시키는 향상된 IBS(EIBS)를 개발하고자 한다. 다른 트리 구성 접근 방식과 비교할 때, 이 논문에서 사용된 방법은 알고리즘이 간단할 뿐만 아니라 전력 소모나 네트워크 수명 면에서 더 효율적이다.

Since Time synchronization is also critical in Wireless Sensor Networks (WSN) like other networks, a time synchronization protocol for WSN called IBS(Indirect-Broadcast Synchronization) has been already proposed in 2012. As IBS operates in cluster tree topology, network lifetime may be mainly shortened by cluster head node[s], which usually consumes more power than cluster member (i.e. non-cluster head) nodes. In this paper, I propose enhanced version of IBS (called EIBS) which saves overall energy and prolongs network lifetime by re-constructing partial cluster tree locally. Compared with other tree construction approaches, this tree reconstruction algorithm is not only simpler, but also more efficient in the light of overall power consumption and network lifetime.

증착된 silicon nitride (Sin) 박막의 수명 시간을 예측하는 신경망 모델을 개발하였다. SiN 박막은 플라즈마 화학기상 증착방식을 이용하여 증착되었다. 증착 공정은 통계적인 실험계획표를 이용하여 수행되었고, 신경망 모델의 예측 성능은 유전자 알고리즘을 이용하여 최적화하였다. 수명시간은 다른 박막특성 (굴절률, 증착률, 전하밀도)의 영향을 상당히 받았으며, 특히 굴절률과 전하밀도는 높은 증착률에서 증가시킬 때 수명시간을 최대화할 수 있었다.

Calender books in Joseon Dynasty consist of two parts: (1)'the study of calender(yeokhak 曆學)' and (2)'the annotation of calendar(yeokju 曆註)’. Yeokhak refers to the first and the fifteenth day of the lunar month (sakmang), the first and the last quater of the moon (sanghahyun)·the twenty-four solar terms (yisipsa julki), solar and lunar eclipses (ylyeolsik) and so on. Yeokju is a study of the principles of yin and yang (陰陽書), identifying misfortune and fortune as well as taboo in daily lives during the year. Yeokhak cannot be understood without susi(授時), one of the examples of the rule of monarchy. susi is the abbreviation of kwansangsusi(觀象授時), which means that the ruler provides his people with a proper knowledge of agriculture by casting a horoscope. Since the ancient time, it was strongly believed that the ruler needs to offer an accurate timetable for agriculture in order to buttress his authority. In this context, it is important to remember that the social life of calendar books was shared by all the people – from the king to ordinary peasants. Ritualistically, the king in Joseon Dynasty granted his ministers the Chinese calendar which he had received from the emperor of China. Nevertheless, the king attempted to monopolize the production and circulation of calendar books. This is the very evidence that he actively intervened in regulating time for his rule. Agriculture was not the only reason the king attempted to predominate over time. By controlling time, the king also tried to intervene in daily events of ordinary people by linking them to his own time. yeokju served for this purpose. It covered a wide scope of everyday lives such as marriage, trade, and movement. By doing so, yeokju incorporated the lives of the king, officials, noble classes, and peasants in to the frame of the sovereign time. Today the linkage between yeokhak and yeokju is considered to be arbitrary. Such linkage seems to be irrational and outdated. The magic of calendar books, which had been still effective in the early Joseon dynasty, fell in to a decline in the late period. As Jung Yakyong(丁若鏞), the famous scholar in the late Joseon period, pointed out, calendar books failed to function in domain of offering correct time, agricultural calender(農曆), and the choice of an auspicious day(擇日). They were nothing but cheap, trivial gifts that people used only once in a while. Although some scholars still emphasize their one-time significance, calendar books were as trivial as scratchbacks or nailclippers. Nevertheless, it is intriguing that the supply of calendar books expanded from one per 400 households in the early Joseon to one per 6 households in the 19th century. Such expansion had little to do with the functional utility of calendar books. Rather, it resulted from the mixture of different ideas and intentions. On the one hand, the king attempted to buttress the rule of monarchy while actualizing the expansion of calendar books through the market device. Given the time sensitive nature of calendar books, the king had to provide more people with more books as quickly as possible, encouraging market trades. On the other hand, people in his time system situated the use of calendar books in different ways according to their different life styles. The rapid spreading of a Confucian ritual in the late Joseon period had made the productive amount of the calendar.