• Korean Journal of Mathematics
• /
• v.23 no.1
• /
• pp.205-230
• /
• 2015

A class of periodic type boundary value problems of coupled impulsive fractional differential equations are proposed. Sufficient conditions are given for the existence of solutions of these problems. We allow the nonlinearities p(t)f(t, x, y) and q(t)g(t, x, y) in fractional differential equations to be singular at t = 0, 1 and be involved a sup-multiplicative-like function. So both f and g may be super-linear and sub-linear. The analysis relies on a well known fixed point theorem. An example is given to illustrate the efficiency of the theorems.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.05a
• /
• pp.260-261
• /
• 2017

The objective of this study is to propose the basic design plan of system by comparing and analyzing application environment of lift and elevator group control system, as preliminary study for the application of group control system to lifts for high-rise construction. The basic design plan is suggested in terms of group control algorithm, hall call system type, operation information recording device, information communication method, and operation method. The results of this study can be used as basic data for software and hardware design for application of group control technology of lifts for super tall building construction and ultimately contribute to improve the operation efficiency of lift for high-rise construction.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.6
• /
• pp.301-308
• /
• 1999

According to the development of power electronic element(GTO, IGBT) and material for electrical machines(permanent magnet, super conductor), the technology for electrical machines is now a day rapidly developing. Here with, a novel electrical machine, based on the new conception of transverse flux configuration leads to a considerable increase in power density and enables simultaneously high efficiency. The designed and measured performance of transverse machine for railway traction system revealed a great potential of system improvements to reduce linear motor mass.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.414-414
• /
• 2000

This paper presents a method for building a real-time kernel of autonomous mobile robot control systems. Until now, most of robots have their own operation softwares dedicated only for their use. Sometimes, operation softwares were developed based on MS-DOS or other real -time kernel based on UNIX. However, MS-DOS has many restrictions for use as a robot operation system. Also, mix based real-time kernel has some Limitations for use with mobile robots. So, in this paper, we focus on building a real-time kernel based on Linux. The in this paper, the software modules of Task Management, Memory Management, Intertask Communication, and Synchronization are redesigned. To show the efficiency of the paper, it was applied to run Nomad Super Scout II avoiding obstacles detected by sonar sensor array.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.5
• /
• pp.157-164
• /
• 2001

The grinding for hard-to-machine materials, such as ceramics, super alloys etc., has proven to be a very difficult and consuming process utilizing ordinary methods. In order to conduct high efficiency machining of such materials, grinding processes using metallic bond diamond wheels and applying electrolytic in-process dressing(ELID) have been attempted on a surface grinding machine. In this study, the effects of grinding parameters, and grit sizes have been evaluated in view of surface roughness, grinding force as well as step difference in simultaneous grinding of different materials. The study and experimental results are presented in this paper.

• Proceedings of the KWS Conference
• /
• 2007.11a
• /
• pp.177-180
• /
• 2007

The laser welding process was effective way to join the metals, because of the high productivity, the low distortion and the good weld quality. The fiber laser used the double-clad fiber architecture, the single element diode laser and the fully-spliced side pumping. It has the advantages in the views of the energy conversion efficiency, the beam quality, the robustness and the mobility. Recently, the thick material was welded with the high power laser in ship building or construction industry owing to the super bright fiber laser. In this study, we introduced the characteristics of high power fiber laser and its welding performance of thick gauge materials.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.8
• /
• pp.1972-1988
• /
• 2013

In order to deal with key exposure problem, we introduce forward secure technique into certificateless proxy signature scheme, and propose the formal definition and security model of the forward secure certificateless proxy signature. Our security model takes into account the super adversary in certificateless signature. Furthermore, we present a construction of forward secure certificateless proxy signature scheme with bilinear maps. Based on the difficulty of computational Diffie-Hellman problem, we prove the scheme is secure against chosen message attack in the random oracle model. Finally, we analyze efficiency of the proposed scheme.

• International Journal of High-Rise Buildings
• /
• v.4 no.2
• /
• pp.109-116
• /
• 2015

The concept of vertical living has been hailed as a solution to control fast growth and urbanization of cities worldwide. As super tall residential projects become more common and sustainability considerations become more necessary, their efficiency has been called into question. How do vertical residential developments compare with suburban homes? What are the environmental advantages and disadvantages of vertical communities? Is there a middle ground? We present the results from an AS+GG study that compares the environmental performance of different housing typologies ranging from a 215 supertall building to single family residences, including several scales in between. Our samples comprise 2,000 residential units per type and include the infrastructure needed to support them. We analyzed land use, energy use, and lifecycle carbon emissions for each typology. The results show that different typologies perform better depending on the parameter being assessed. We discuss these findings; assess overall performance, and present conclusions.

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.1153-1155
• /
• 1998

Super-conducting Magnetic Energy Storage(SMES) system is considered to be useful unit to power system stabilizer because of high efficiency and quick response. For effective operating of SMES, we need much studies on accurate modeling and interface characteristics of SMES. In this paper, we propose useful method to SMES, modeling using Artificial Neural Network. Interface technique of proposed model and criterion of stabilization effect is presented. In addition, to demonstrate the validity of proposed method. the simulations were carried out on 3-machine 9-bus system.

• Proceedings of the KIEE Conference
• /
• 1999.07a
• /
• pp.427-429
• /
• 1999

According to the development of power electronic element(GTO. IGBT) and material for electrical machines(permanent magnet. super conductor), the technology for electrical machines is now a day rapidly developing. Here with, a novel electrical machine, based on the new conception of transverse flux configuration leads to a considerable increase in power density and enables simultaneously high efficiency. The transverse flux machine with PM excitation will be applied to gearless direct drives for railway traction system. The designed and measured performance of transverse machine for railway traction system revealed a great potential of system improvements to reduce linear motor mass.