• International Journal of Internet, Broadcasting and Communication
• /
• 제12권3호
• /
• pp.46-55
• /
• 2020

Ad Hoc network is a special wireless network, mainly because the nodes are no control center, the topology is flexible, and the networking could be established quickly, which results the transmission stability is lower than other types of networks. In order to guarantee the transmission of data packets in the network effectively, an improved Queue Ad Hoc On-demand Distance Vector Routing protocol (Q-AODV) for node detection by using blockchain technology is proposed. In the route search process. Firstly, according to the node's daily communication record the cluster is formed by the source node using the smart contract and gradually extends to the path detection. Then the best optional path nodes are chained in the form of Merkle tree. Finally, the best path is chosen on the blockchain. Simulation experiments show that the stability of Q-AODV protocol is higher than the AODV protocol or the Dynamic Source Routing (DSR) protocol.

• Corrosion Science and Technology
• /
• 제17권2호
• /
• pp.81-89
• /
• 2018

In this study, the effect of Nb alloying element on the corrosion fatigue properties of high strength steel is investigated by conducting fatigue experiments under corrosive condition and hydrogen induced condition, potentiodynamic polarization test, tensile test and surface analyses. Nb element is added to enhance the mechanical property of medium carbon steel. This element forms MX-type phases such as carbides and nitrides which are playing an important role in the grain refinement. The grain refinement is one of the effective way to improve mechanical property because both tensile strength and toughness can be improved at the same time. However, MX-type phase precipitates can be a susceptible site to localized corrosion in corrosive environment due to the potential difference between matrix and precipitate. The obtained results showed that Nb-added steel improved corrosion fatigue property by grain refinement. However, it is degraded for hydrogen-induced fatigue property due to Nb, Ti-inclusions acting as a stronger trap.

• 한국유체기계학회 논문집
• /
• 제10권2호
• /
• pp.46-53
• /
• 2007

An improved performance characteristics analysis model of a regenerative pump is proposed in the present paper. For its low characteristic speed, a regenerative pump generates high head with low flow rate. However, the efficiency is fairly low due to the skin friction between impeller and casing. Also, the complexity of its internal flow pattern makes prediction of performance characteristics difficult. In the present research, a one-dimensional analysis model was improved with consideration of disc friction loss, minor loss, and modified flow length, and the result was proven to be close in range with the results from experiments.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 추계학술대회 논문집
• /
• pp.214-219
• /
• 2001

For navigation of a mobile robot, it is one of the essential tasks of find out its current position. Dead reckoning is the most frequently used method to estimate its position. However conventional dead reckoner is prone to give us false information on the robot position especially when the wheels are slipping. This paper proposes an improved dead reckoning scheme using neural networks. The network detects the instance of wheel slipping and estimates the linear velocity of the wheel ; thus it calculates current position and heading angel of a mobile robot. The structure and variables of the neural network are chosen based on the analysis of slip motion robot. The structure and variables of the neural network are chosen based on the analysis of slip motion characteristics. A series of experiments are performed to investigate the performance of the improved dead reckoning system.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.162-165
• /
• 2004

On this study, we improved diaphgram for micro speaker performance using Taguchi method in discrete design space. The design of diaphgram has an effect on performance of micro speaker such as, thickness of diaphgram, shape of diaphgram, etc. Therefore this study carried to decide shape of diaphgram and thickness of diaphgram for minimizing 2nd natural frequency of diaphgram using Taguchi method. we showed improved design factors that minimized 2nd natural frequency of diaphgram. Also, 2nd natural frequency of diaphgram for micro speaker is reduced up to 37 percent maintaining twist mode shape. From the results of ANOVA, 2nd natural frequency of diaphgram for micro speaker have an effect on position of the outer curved shape and thickness of diaphgram.

• 한국정보통신학회논문지
• /
• 제10권10호
• /
• pp.1848-1853
• /
• 2006

본 논문에서는 3차원 집적 영상 기술에서 렌즈배열 모델을 적용하여 컴퓨터적으로 해상도가 개선된 3차원 영상을 재생하는 방법을 제안하고, 그 성능을 분석한다. 기존의 보고된 컴퓨터 적 시점 재생 방법은 핀홀 배열 모델에 기초하지만, 제안하는 방법은 렌즈 배열 모델을 적용하기 때문에 동일한 요소영상에서 다수의 픽셀을 추출하여 높은 해상도를 얻을 수 있다. 제안한 방법의 유용함을 보이기 위해 기초적인 실험을 수행하고 그 결과를 보고한다.

• 한국생산제조학회지
• /
• 제25권1호
• /
• pp.36-41
• /
• 2016

A method is proposed for the improvement of deposition reproducibility in the selective electrodeposition process using laser masking and DC voltage. Selective electrodeposition using laser masking and DC voltage can achieve a deposited layer with micro patterns. However, selective electrodeposition using laser masking and DC voltage have a critical problem: the lack of reproducibility in selective deposition. The reproducibility of selective electrodeposition can be improved by a new process that consists of laser masking, two-step electro-deposition, laser scribing, and ultrasonic cleaning. The experiments in this study show that the reproducibility of selective deposition can be successfully improved by the combination of two-step electrodeposition and laser scribing.

• The Journal of the Acoustical Society of Korea
• /
• 제16권2E호
• /
• pp.32-37
• /
• 1997

This paper proposes a isolated speech recognition method of Korean digits using a TDNN(Time Delay Neural Network) which is able to recognizc time-varying speech properties. We also make an investigation of effect on network parameter of TDNN ; hidden layers and time-delays. TDNNs in our experiments consist of 2 and 3 hidden layers and have several time-delays. From experiment result, TDNN structure which has 2 hidden-layers, gives a good result for speech recognition of Korean digits. Mis-recognition by time-delays can be improved by changing TDNN structures and mis-recognition separated from time-delays can be improved by changing input patterns.

• 반도체디스플레이기술학회지
• /
• 제12권1호
• /
• pp.1-7
• /
• 2013

Grey-level statistical models have been widely used in many applications for object location and identification. However, conventional models yield some problems in model refinement when training images are not properly aligned, and have difficulties for real-time recognition of arbitrarily rotated models. This paper presents improved grey-level statistical models that align training images using image or feature matching to overcome problems in model refinement of conventional models, and that enable real-time recognition of arbitrarily rotated objects using efficient hierarchical search methods. Edges or features extracted from a mean training image are used for accurate alignment of models in the search image. On the aligned position and orientation, fitness measure based on grey-level statistical models is computed for object recognition. It is demonstrated in various experiments in PCB inspection that proposed methods are superior to conventional methods in recognition accuracy and speed.

• 제어로봇시스템학회논문지
• /
• 제18권11호
• /
• pp.1027-1033
• /
• 2012

Semantic-based information retrieval techniques understand the meanings of the concepts that users specify in their queries, but the traditional semantic matching methods based on the ontology tree have three weaknesses which may lead to many false matches, causing the falling precision. In order to improve the matching precision and the recall of the information retrieval, this paper proposes a multi-agent improved semantic similarity matching algorithm based on the ontology tree, which can avoid the considerable computation redundancies and mismatching during the entire matching process. The results of the experiments performed on our algorithm show improvements in precision and recall compared with the information retrieval techniques based on the traditional semantic similarity matching methods.