• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.11 s.353
• /
• pp.78-84
• /
• 2006

This paper proposes a method to endow the mobility to the Zigbee protocol which is a short distance wireless communication technology among the standards of wireless sensor networks. The Zigbee has a low price, long life battery, simple structure and connectivity. So it is a suitable standard for the short distance wireless communication of $10m{\sim}70m$. As the Zigbee does not support the mobility, additional factors should be studied to deal adeptly with the diverse change in the real field. By solving the problem that the previous connection and binding table of the Zigbee end device should be reset due to the Zigbee end device address variation when the Zigbee end device moves from the present router to another router, this paper presents the method to communicate without data loss or disconnection.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.6
• /
• pp.609-617
• /
• 2014

Even though the variable pitch control of a wind turbine blade is known as an effective component for power control over the rated wind speed, it has limited applicability to small wind turbines because of its relatively high cost on the price of small wind turbine. Instead, stall control is generally applied in the blade design without any additional cost. However, stall delay can frequently be caused by high turbulence around the turbine blade, and it can produce control failures through excessive rotational speed and overpowering the electrical generator. Therefore, a passive pitch control module should be considered, where the pitch moves with the aerodynamic forces of the blade and returns by the elastic restoring force. In this study, a method to calculate the pitch moment, torque, and thrust based on the lift and drag of the rotating blade wing was demonstrated, and several effective wing shapes were reviewed based on these forces. Their characteristics will be estimated with variable wind speed and be utilized as basic data for the design of the passive pitch control module.

• Journal of the Korea Computer Graphics Society
• /
• v.19 no.2
• /
• pp.1-8
• /
• 2013

Captured human motion data has been widely utilized for understanding the mechanism of human motion and synthesizing the animation of virtual characters. Searching for desired motions from given motion data is an important prerequisite of analyzing and editing those selected motions. This paper presents a new method of content-based motion retrieval without the need of additional metadata such as keywords. While existing search methods have focused on skeletal configurations of body pose or planar trajectories of locomotion, our method receives a three-dimensional trajectory as its input query and retrieves a set of motion intervals in which the trajectories of body parts such as hands, foods, and pelvis are similar to the input trajectory. In order to allow the user to intuitively sketch spatial trajectories, we used the Leap Motion controller that can precisely trace finger movements as the input device for our experiments. We have evaluated the effectiveness of our approach by conducting a user study in which the users search for dozens of pre-selected motions from baseketball motion data including a variety of moves such as dribbling and shooting.

• The Korean Journal of Ceramics
• /
• v.4 no.4
• /
• pp.323-330
• /
• 1998

Mixed oxide compounds of potential usefulness for fibre coatings (hexagonal celsian, $BaAl_2Si_2O_8$ and lanthanum hexaluminate, $LaAl_{11}O_{18}$) or for matrix materials (yttrium aluminium garnet, $Y_3Al_5O_{12}$) were prepared by hybrid sol-gel synthesis and their thermal crystallisation was monitored by thermal analysis, X-ray diffraction and multinuclear solid state MAS NMR. All the gels convert to the crystalline phase below about $12200^{\circ}C$, via amorphous intermediates in which the Al shows and NMR resonance at 36-38 ppm sometimes ascribed to Al in 5-fold coordination. Additional information about the structural changes during thermal treatment was provided by $^{29}Si$, $^{137}Ba$ and $^{89}Y$ MAS NMR spectroscopy, showing that the feldspar framework of celsian begins to be established by about $500^{\circ}C$ but the Ba is still moving into its polyhedral lattice sites about $400^{\circ}C$ after the sluggish onset of crystallization. Lanthanum hexaluminate and YAG crystallise sharply at 1230 and $930^{\circ}C$ respectively, the former via $\gamma-Al_2O_3$, the latter via $YAlO_3$. Yttrium moves into the garnet lattice sites less than $100^{\circ}C$ after crystallisation.

• Journal of the Korea Society of Computer and Information
• /
• v.23 no.6
• /
• pp.9-14
• /
• 2018

This paper focuses on how the latest progress in digital media and technology affects the writing education environment. In the contemporary era, collecting numerous pices of information online, and arranging them to create new knowledge is important. There is also a need to seek new methods for writing education to stay in tune with the times. To that end, this paper suggests an open writing model using hypertexts. This writing model consists of a total of five stages, which are use of information, compilation of information, open mutual discussion, search of additional information and writing to recreate knowledge. The final outcome of such writing is writing using footnotes. By describing the gist of the keyword and adding numerous footnotes, such writing opens up an infinite possibility of re-creating information into new knowledge. This method can help university students who are accustomed to the digital society to proactively use information and improve multi-disciplinary communication skills required today. This author applied such a model to university writing education and found that more than 82% of the students were satisfied. Through the process of collaboration and recreation of knowledge in writing, learners found distinct benefits and noted their horizons had broadened. Given this effect, the open writing model using hypertexts is meaningful in that it forms a learning community that goes beyond a one-way feedback from instructor to student and instead nudges students to realize collective intellect. Moreover, it is meaningful in that it moves away from a top-down approach of the instructors passing down knowledge about writing and its rules, and towards a more proactive involvement by students in creating knowledge.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.6C
• /
• pp.535-543
• /
• 2002

In order to overcome disadvantages of existing centralized network management systems that use simple objects, dynamic object platforms are proposed as alternative systems. So the distributed network management systems are implemented using various distributed platform such as CORBA and Java-RMI. Subsequently mobile agent-based platforms are proposed. The mobile agent-based platform can additionally provide flexibility and scalability to network management system that CORBA or Java-RMI based platforms do not support. In this paper, we address an architecture to solve the problem of the occurrence of additional traffic by using mobile agent and to save resources of network element. Our proposal in this paper is an efficient network management architecture using motile agents. And we make use of mobile agents for minimizing of traffic that can happen when mobile agents moves. Also we design agents using information architecture of TMN for efficient resource management of network element and improvement of operation performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.98-101
• /
• 2011

Recently with the advent of Web 2.0 mashups are Web services, a new concept is in the spotlight. Mashups with Web services, such as a new concept for the purposes of an individual's social networking community type social network service web service coming seeping deep into our lives was a huge pillars. The structure of the network of one-way, tweeter and horizontal moves are also suitable for biased information. People from twitter's vast social network that matches their area of interest and share information with people who are wanted. In this paper, we develop the smart retweet mashup service that matching areas of interest for the purpose of sharing information between people. To selectively share information and consideration, additional information is required. Information derived from user-specified area of interest by region and share information is selectively targeted.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.3B
• /
• pp.349-359
• /
• 2004

To provide multicasting service, several multicast protocols for mobile hosts have been proposed. But they include glitches such as a non-optimal delivery route, data loss when hosts move another network, therefore they have some insecure problems about multicast data transmission. In this paper, we consider these problems and propose a new reliable and efficient multicast routing protocol for Mobile If networks. The proposed protocol provides reliable multicast transmission by compensating data loss from the previous agent when a mobile host moves another network. Also it provides additional function that is directly to connect a multicast tree according to the status of agents. It provides more efficient and optimal multicast path. The performance of the proposed protocol is proved by simulation of various conditions.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.5
• /
• pp.119-131
• /
• 2009

Existing proposals on route optimization for nested Network Mobility(NEMO) have a problem that it is difficult to optimize a route promptly in an environment where a MR moves frequently. Also, they have L3 handoff latency as well as route optimization latency until an optimized route is formed. In this paper, we propose a L3 handoff scheme that supports fast route optimization for nested NEMO without any additional optimization procedure. To achieve this, our proposed scheme is designed to include a procedure that an AR acquires address informations of a MR. After receiving binding update message from the MR, the AR performs the binding update procedure with the MR's HA on behalf of the MR. Packets are delivered to the AR only passing by the MR's HA after a bi-directional tunnel is formed between the AR and the HA. The result of our performance evaluation has shown that the proposed scheme could provide excellent performance compared with the RRH and the ONEMO.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.43 no.2 s.308
• /
• pp.30-39
• /
• 2006

Iris recognition is that identifies a user based on the unique iris texture patterns which has the functionalities of dilating or contracting pupil region. Iris recognition systems extract the iris pattern in iris image captured by iris recognition camera. Therefore performance of iris recognition is affected by the quality of iris image which includes iris pattern. If iris image is blurred, iris pattern is transformed. It causes FRR(False Rejection Error) to be increased. Optical defocusing is the main factor to make blurred iris images. In conventional iris recognition camera, they use two kinds of focusing methods such as lilted and auto-focusing method. In case of fixed focusing method, the users should repeatedly align their eyes in DOF(Depth of Field), while the iris recognition system acquires good focused is image. Therefore it can give much inconvenience to the users. In case of auto-focusing method, the iris recognition camera moves focus lens with auto-focusing algorithm for capturing the best focused image. However, that needs additional H/W equipment such as distance measuring sensor between users and camera lens, and motor to move focus lens. Therefore the size and cost of iris recognition camera are increased and this kind of camera cannot be used for small sized mobile device. To overcome those problems, we propose method to increase DOF by iris image restoration algorithm based on focus value of iris image. When we tested our proposed algorithm with BM-ET100 made by Panasonic, we could increase operation range from 48-53cm to 46-56cm.