• Journal of KIISE:Computer Systems and Theory
• /
• v.37 no.1
• /
• pp.55-59
• /
• 2010

Most applications for solar-powered wireless sensor networks are usually deployed in remote areas without a continuous connection to the external networks and a regular maintenance by an administrator. In this case, sensory data has to be stored in the network as much as possible until it is uploaded by the data mule. For this purpose, a balanced data distribution over the network should be performed, and this can be achieved efficiently by taking the amount of available energy and storage into account, in the system layer of each node. In this paper, we introduce a simple but very efficient data distribution algorithm, by which each solar-powered node utilizes the harvested energy and the storage space maximally. This scheme running on each node determines the amount of energy which can be used for a data distribution as well as the amount of data which should be transferred to each neighbor, by using the local information of energy and storage status.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.2
• /
• pp.99-106
• /
• 2003

This paper presents a novel multilevel PWM inverter employing series-connected transformers in order to improve the waveshape of output voltage and to reduce its harmonics. The proposed 11-level inverter consists of three full-bridge inverter modules and their corresponding transformers. Among their inverter modules, one is used as PWM operation and the others as level generation. From a suitable selection of turns ratio of transformer, continuous output voltage levels were generated appearing an integral ratio to input DC source. Because of their series connection of transformers, output filter inductor is not necessary. The operational principles and analysis are explained, and it is compared with a conventional multilevel PWM inverter. The validity of the proposed system Is verified through the experimental results using a prototype.

• Journal of the Korea Concrete Institute
• /
• v.27 no.1
• /
• pp.55-63
• /
• 2015

Prefabrication technologies are making bridge construction safer and less disruptive to the environment and traveling public, making bridge designs more constructible and, improving the quality and durability by shifting site work to a more controllable environment. Modular bridge substructures with concrete-filled steel tube (CFT) piers and composite pier caps were suggested to realize accelerated bridge construction. The precast segmental pier cap consists of a composite pier table and precast prestressed segments on the table. The pier table has embedded steel section to mitigate stress concentration at the connection by small tubes. Each bridge pier has four or six CFT columns which connect to the pier cap. Shear strength of the pier cap was obtained by extending vertical reinforcing bars from the table to the precast segment. Transverse prestressing was introduced to control tensile stresses by service loadings. Structural performance of the proposed modular system was evaluated by static tests. Design requirements of the composite pier cap were satisfied by continuous reinforcing bars and prestressing tendons. Standardized modular substructures can be effectively utilized for the fast replacement or construction of bridges.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.8
• /
• pp.1023-1028
• /
• 2010

Recently, an intelligent service robot is being developed for use in guiding and providing information to visitors about the building at public institutions. The intelligent robot has a sensor at the bottom to recognize its location. Four wheels, which are arranged in the form of a lozenge, support the robot. This robot cannot be operated on uneven ground because its driving parts are attached to its main body that contains the important internal components. Continuous impact with the ground can change the precise positions of the components and weaken the connection between each structural part. In this paper, the design of the suspension system for such a robot is described. The dynamic model of the robot is created, and the driving characteristics of the robot with the designed suspension system are simulated. Additionally, the suspension system is optimized to reduce the impact for the robot components.

• Journal of Industrial Convergence
• /
• v.17 no.4
• /
• pp.87-94
• /
• 2019

The purpose of this study is to predict the usefulness and predictable effects of the use of dementia prevention games and dementia management applications provided in smart-phones for the elderly. First, 6 dementia diagnostic tools used to verify the effectiveness of the dementia prevention program were selected and the cognitive domains tested by each diagnostic tool were extracted. Second, 29 smart-phone dementia prevention game applications and dementia management applications were selected and the expected effects after using these applications were analyzed in connection with the cognitive domain extracted from the dementia diagnosis tool. As a result, it was expected that it would be helpful to manage dementia prevention by improving cognitive function in certain areas when playing games or managing dementia continuously using smart-phone dementia prevention applications. Smart-phone dementia prevention applications will be useful in improving the cognitive ability of the elderly and preventing dementia by supplementing the limitations of the dementia prevention program that is operated offline through time-space ease of use, continuous usability and economic feasibility.

• The Korean Journal of Zoology
• /
• v.3 no.2
• /
• pp.1-4
• /
• 1960

Urticating spicules and poison -secreting cells of the last instar larva in Euproctis flava BREMER was studied histologically. Three kinds of cells in the epidermis of tubercles on the lst to 8th abodominal segments are classified according to the arrangement of their nuclei : smallepidermal cells, large gland cells, and elongated trichogen cells. As a result of Mallory's triple straining , the epicuticle , the papila-like structure apart form the tubules inside which are gathered at the base and connected with a middle layer cell through a canal in the cuticle, and the peripheral of the urticating spcicule are yellow. However, the inside of the spicule , the tubules within the papilla-like structure, the canal in the cuticle , nuclei in the pidermal cells and the thin exocuticle are red although the thich endocuticle is blue. Particularly , the large nuclei in the middle layer cells are bright red, the cytoplasms of which are little and stained red, too, and the inside of the spicules apt to be stained red when they are broken. The contents therefore seem to be continuous between the spicules and the large cells. Presumably , the large cell at the middle layer is not te tormogen cell which Tsutsumi (1958) has described , but the gland cell which secretes the poison-substance into spicules as Pawlowsky and Stein 91927) and Tonkes (1933) pointed out. Whether the pisonous substance is secreted from the gland cell into the cytoplasmic processes of the trichogen cells which stick large middle layer cells during the formation of the new spicule as Tsutsumi (1958) has observed, or the gland cell makes a new connection with the spicule after the spicule is formed is not clear.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.1
• /
• pp.344-357
• /
• 2015

With the increase in a number of access technologies and data rates, a continuous connection among different networks is demand of the future wireless networks. In the last decade, user connectivity among different access networks remained a challenging job. Therefore, in this article, we proposed a user-centric and user-perspective based network selection mechanism for fast handover management in heterogeneous wireless networks. The proposed scheme selects the most appropriate network among available networks on the basis of resources i.e. cost, data rate, and link quality. Initially, we load the Media Independent Information Service (MIIS) with the information of cost and data rate provided by different network operators. Similarly, Mobile Node (MN) is also loaded with the user preferred cost and data rate for different applications. The MN obtains the information of cost and data rate from MIIS server upon a predefined threshold, and make a decision for handover according to its current cost and data rate. Furthermore, we employ an optimal threshold mechanism for initiation of the handover execution phase to minimize false handover indications. The proposed scheme is based on a survey for network selection and its implementation in C programming language to validate its performance and accuracy. The simulation result shows that the proposed scheme performs superior then the schemes present in the current literature.

• The Korean Nurse
• /
• v.31 no.5
• /
• pp.53-64
• /
• 1992

A nurse is give much weight in the professions of hospital.The effective achievement of a goal of hospital organization needs to get nurses to contribute the structure positively through the rational personnel management of the nurses.The operation of performance rating system is necessary to improve because the nurses hold negative opinions about the resonable management of that system in most Korean hospitals.Therefore, the prupose of this research was to suggest an efficient method to solve the problem in connection with the management of nurses performance rating system.The results of the study are summarized as follows.1. As the performance rating implies the evaluation of employee's functional accomplishment and ability, and essential condition of the job was surveyed according to the job analysis of nursing activities and nurse position.That is to say, Nusrses' performances and capability is estimated in comparision with the condition of the job. 2. It is required adequacy for evaluation factors in performance rating.That is, $\circled1$ as for those who work in psychiatry or newborn baby room they should be appraied in terms of different factors from those applicable to whom work in a general staffs. $\circled2$ Evaluation factors should be concrete so that the quality and quantity of work and the potential ability of them can be correctly appraised. 3. In order to realize the object of perfamance rating system, the training on chief nurses are quite important. Also, careful practices and continuous supplementary training are required before the system is introduced.First of all, the appropriate evaluation can be mad by continuing to record the rating objects every day for the purpose of obtaining the objectivity of rating. 4. In course of transfering of the position and training, the induction of self-rating system and presentation of self-description is required to supplement functionally the performance rating system. 5. For the efficiency of nurses' performance rating system, the results of performance rating system must be reflected in promotion, allocation and training course, which makes the nurses have the motives and the organization accomplish the goal of modern nursing through its activation.

• Journal of Wetlands Research
• /
• v.14 no.4
• /
• pp.637-644
• /
• 2012

The discharge estimation that means the most important element in a wetlands ecosystem and rivers is a prime concern. All the interim, this discharge estimation depends on stage-discharge curve, but the limitation of stage-discharge curve that uses only connection between the stage and discharge is widely well known. Thus, this paper proposed a method of discharge estimation in a section through "representative parameter estimation method" by using Manning and Chezy equations that have been extensively used in an open channel. Each result is presented by both RMSE and Discrepancy Ratio. The scale difference for the results between laboratory and natural open channel data existed, but the each result showed that the estimated discharge agree with the measured discharge. If the verification and improvement are conducted in various rivers through continuous study, the easy and rapid discharge estimation will be possible. So, the proposed method will be utilized in the water resources fields.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39B no.2
• /
• pp.75-85
• /
• 2014

Recently, mobile SNS traffic has increased tremendously due to the deployment of smart devices such as smart phones and smart tablets. In this paper, mobile integrated SNS gateway is proposed to cope with massive SNS traffic. Most of mobile SNS applications update the information with individual connection to the corresponding servers. The proposed gateway integrates these applications. It is for reducing SNS traffic caused by continuous data request and improving the mobile communication performance. The key elements of the mobile integrated SNS gateway are the synchronization, cache and integrated certification. The proposed protocol and gateway system have implemented on the testbed which deployed on the real network to evaluate the performance of the proposed gateway. Finally, we present the caching performance of gateway system implementation.