• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.296-300
• /
• 2003

The autopilot system targets decreasing labor, working environment improvement, service safety security and elevation of service efficiency. Ultimate purpose is minimizing number of crew for guarantee economical efficiency of shipping service. Recently, being achieving research about Course Keeping Control, Track Keeping Control, Roll-Rudder Stabilization. Dynamic Ship Positioning and Automatic Mooring Control etc. which compensate nonlinear characteristic using optimizing control technique. And application research is progressing using real ship on actual field. Relation of Rudder angle which adjusted by Steering Machine and ship-heading angle are non-linear. And Load Condition of ship as non-linear element that influence to Parameter of ship. Also, because the speed of a current and direction of waves, velocity and quantity of wind etc. that is disturbance act in non-linear from, become factor who make serv ice of shipping painfully. Therefore, service system of shipping requires robust control algorithm that can overcome nonlinearity. In this paper, Using fuzzy algorithm ,Design autopilot system of ship that could overcome the non-linear factor of ship and disturbance and examined result through simulation.

• Korea Journal of Hospital Management
• /
• v.19 no.4
• /
• pp.45-56
• /
• 2014

Purpose: This study aims to explore the effects of personal characteristics, satisfaction, quality of care, role performance, image, awareness level of public hospitals perceived by community residents on use-experience of public hospitals. Methods: A cross-sectional survey was conducted with 2,100 community residents around 39 district public hospitals. The questionnaire was designed to collected information on personal characteristics and community awareness of public hospitals. The community awareness consists of 5 factors and 15 items. The data were collected utilizing call-interview by a survey company. Results: The personal characteristic and community awareness were shown significant differences between having use-experience and not-having use-experience of public hospitals (p<.001), except gender. As the results of multiple logistic regression, the significant variables of use-experience of public hospitals were satisfaction (OR=1.06 95%CI=1.010-1.116), quality of care (OR=1.07, 95%CI=1.016-1.134, level of awareness to public hospitals (OR=1.50, 95%CI=1.378-1.632), age (OR=0.43, 95%CI=0.236-0.785), education (OR=1.62, 95%CI=1.013-2.590), type of medical security (OR=0.37, 95%CI=0.142-0.945). Conclusions: Public hospitals have to effort to improve community awareness through providing quality of care, and role performance. It is possible to support them by the Central and Local Government.

• Journal of Environmental Impact Assessment
• /
• v.17 no.6
• /
• pp.335-348
• /
• 2008

The purpose of this study is to classify the cities on sustainability assessment score studied in advance using cluster analysis, to present efficient management and policy direction based on analysis of sustainability index in 45 cities of all over Gyeongsangnam and Gyeongsangbuk-do. According to the results of cluster analysis, 45 cities were classed into 4 clusters by "livable-welfare city", "environmental -ecological city", "scientific-technological city", and "industrial-economic city". The livable-welfare cities must keep superior environmental sustainability, promote small and medium sized business on regional characteristic. The environmental-ecological cities have to change agriculture into future environmental industry such as ecotourism, bio-industry and landscape agriculture. The scientific-technological cities are going to need support of government scale such as income enlargement of citizen and stable job security. Finally, the industrial-economic cities must increase environmental management plants and improve quality of life through securing green spaces, maintaining public peace and applying UIS because of low quality of environment and life.

• Journal of Internet Computing and Services
• /
• v.3 no.5
• /
• pp.87-94
• /
• 2002

This paper proposes a group key management protocol for a secure of all the multcast user in PIM-SM multicast group communication. Each subgroup manager gives a secure key to it's own transmitter and the transmitter compress the data with it's own secure key from the subgroup manager, Before the transmitter send the data to receiver, the transmitter prepares to encrypt a user's service by sending a encryption key to the receiver though the secure channel. after checking the user's validity through the secure channel, As the transmitter sending a data after then, the architecture is designed that the receiver will decode the received data with the transmitter's group key, Therefore, transmission time is shortened because there is no need to data translation by the group key on data sending and the data transmition is possible without new key distribution at path change to shortest path of the router characteristic.

• Korean Institute of Interior Design Journal
• /
• v.20 no.2
• /
• pp.156-166
• /
• 2011

A studio type urban lifestyle housing was recently introduced as a new urban multi-housing typology. It was particularly created to meet the increasing housing demand of one-person households due to the population change and the shortage of housing supply. However, some concerns have been raised, because the government's policy has been focused on expanding housing supply by easing certain legal regulations in construction. Poorly planned and managed urban lifestyle housings might degrade living conditions for one-person households and ultimately harm urban environments. As such, this research is conducted to investigate the design characteristics of the studio type urban lifestyle housing from selected construction precedents in Seoul. Critical evaluations are made for the facilities and uses in site plans, unit plans, and shared public spaces. As a result, problem areas are found in the lack of design varieties, privacy protection in units, control of natural environment conditions, and the absence of community spaces. Improvement strategies can be suggested by comparing with some overseas' housing precedents: Design variations can be extended through flexible structure, facility, and furniture systems. Privacy and natural environment can be controled through the integration of interior space configurations and exterior envelope systems. The housing policy needs to be reconsidered to improve a variety in design, residents' social interaction, security, and management. Thereby, the studio type urban lifestyle housing should be holistically approached in terms of design and policy to enrich urban living experiences by residents and communities.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.58 no.6
• /
• pp.47-54
• /
• 2016

This study is a basic research on the functional performance review for the use of environmentally friendly construction materials as lapilli-bio block. The neutralization processed Mt. Backdusan and Mt. Hallasan lapilli-bio block were identified vegetation characteristics and water purification properties. As a result, the adsorption of root was more favorable, depending on the material properties of many voids Lapilli. And if the neutralization processed lapilli-bio blocks maintain a long-term immersion conditions in contaminated water was found to be expected from the improvement effect of SS, T-N and T-P. However, field trials and continuous studies are expected to be identified by the use of lapilli-bio block.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.31 no.3
• /
• pp.117-124
• /
• 2008

Ultra-high voltage transformer industry has characteristic of small quantity batch production system by other order processing unlike general mass production systems. In this industry, observance of time deadline is very important in market competitive power security and company continued existence. The transformer winding is a process that rolls a coil is coated with an electric insulation material in order to generate the required voltage using the voltage fluctuation. The winding process is very important production process in the extra-high voltage transformer manufacturing industry because winding process is core process that occupy weight about half of whole process and is process that decide current ratio of transformer. This paper proposes a statistical calculation and control method of planned leadtime on the basis of real data and informations for the A company in transformer winding process. Moreover, we develop unit process scheduling system.

• Journal of Power Electronics
• /
• v.17 no.1
• /
• pp.305-313
• /
• 2017

A novel interference isolation method is proposed by using several designed coils in capacitive power transfer systems as isolation impedances. For each designed coil, its stray parameters such as the inter-turn capacitance, coil resistance and capacitance between the coil and the core, etc. are taken into account. An equivalent circuit model of the designed coil is established. According to this equivalent circuit, the impedance characteristic of the coil is calculated. In addition, the maximum impedance point and the corresponding excitation frequency of the coil are obtained. Based on this analysis, six designed coils are adopted to isolate the interference from power delivery. The proposed method is verified through experiments with a power carrier frequency of 1MHz and a data carrier frequency of 8.7MHz. The power and data are transferred parrallelly with a data carrier attenuation lower than -5dB and a power attenuation on the sensing resistor higher than -45dB.

• Journal of Communications and Networks
• /
• v.15 no.5
• /
• pp.457-463
• /
• 2013

In recent days, cooperative diversity and communication security become important research issues for wireless communications. In this paper, to achieve low probability of interception (LPI) and high throughput in the cooperative single-carrier frequency division multiple access (SC-FDMA) system, a new physical layer transmission scheme is proposed, where a new encryption algorithm is applied and adaptive modulation is further considered based on channel state information (CSI). By doing so, neither relay node nor eavesdropper can intercept the information signals transmitted from user terminal (UT). Simulation results show above new physical layer transmission scheme brings in high transmission safety and secrecy rate. Furthermore, by applying adaptive modulation and coding (AMC) technique according to CSI, transmission throughput can be increased significantly. Additionally, low peak-to-average power ratio (PAPR) characteristic can still be remained due to the uniform distribution of random coefficients used for encryption algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.8
• /
• pp.3550-3566
• /
• 2020

As a widely used way to exfiltrate information, wireless covert channel (WCC) brings a serious threat to communication security, which enables the wireless communication process to bypass the authorized access control mechanism to disclose information. Unlike the covert channel on the network layer, wireless covert channels on the physical layer (WCC-P) is a new covert communication mode to implement and improve covert wireless communication. Existing WCC-P scheme modulates the secret message bits into the Gaussian noise, which is also called covert digital communication system based on the joint normal distribution (CJND). Finding the existence of this type of covert channel remains a challenging work due to its high undetectability. In this paper, we exploit the square autocorrelation coefficient (SAC) characteristic of the CJND signal to distinguish the covert communication from legitimate communication. We study the sharp increase of the SAC value when the offset is equal to the symbol length, which is caused by embedding secret information. Then, the SAC value of the measured sample is compared with the threshold value to determine whether the measured sample is CJND sample. When the signal-to-noise ratio reaches 20db, the detection accuracy can reach more than 90%.