• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.4
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• pp.187-194
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• 2018

The operating system for IoT should have a small memory footprint and provide low power state, real-time, multitasking, various network protocols, and security. Although the Zephyr kernel, an operating system for IoT, released by the Linux Foundation in February 2016, has these features but errors generated by the user code can generate fatal problems in the system because the Zephyr kernel adopts a single-space method that both the user code and kernel code execute in the same space. In this research, we propose a space separation method, which separates kernel space and user space, to solve this problem. The space separation that we propose consists of three modifications in Zephyr kernel. The first is the code separation that kernel code and user code execute in each space while using different stacks. The second is the kernel space protection that generates an exception by using the MPU (Memory Protection Unit) when the user code accesses the kernel space. The third is the SVC based system call that executes the system call using the SVC instruction that generates the exception. In this research, we implemented the space separation in Zephyr v1.8.0 and evaluated safety through abnormal execution of the user code. As the result, the kernel was not crashed by the errors generated by the user code and was normally executed.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.5
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• pp.253-260
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• 2014

European Space Agency has recognized Integrated Modular Avionics and ARINC specification 653 as avionics computer system for space application. Integrated Modular Avionics specification reduces the space by integrating a system composed of many electronic devices into a computer. recent researches have been studying how to apply the ARINC 653 into an open source operating system, such as Linux. These studies have concentrated on partition scheduling for time separation. However, requirements to guarantee spatial separation should be further analyzed to ensure deterministic execution time. Therefore, memory management is needed to verify spatial isolation on Linux systems. This research proposes a new method to accomplish spatial isolation for the ARINC 653 specification in Linux. We have added new data structures and system calls to handle functionalities for spatial separation. They are used during the partition startup process. The proposed method was evaluated on the LEON4 processor, which is the next generation microprocessor to be used in the future space missions. All implementations confirm that spatial isolation of the ARINC 653 specification was accomplished.

• International Journal of Aeronautical and Space Sciences
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• v.2 no.2
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• pp.1-18
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• 2001

A numerical technique for simulating the separation dynamics of strap-on boosters jettisoned in the dense atmosphere is presented. Six degree of freedom rigid body equations of motion are integrated into the three-dimensional unsteady Navier-Stokes solution procedure to determine the dynamic motions of strap-ons. An automated Chimera overlaid grid technique is introduced to achieve maximum efficiency for multi-body dynamic motion and a domain division technique is implemented in order to reduce the computational cost required to find interpolation points in the Chimera grids. The flow solver is validated by comparing the computed results around the Titan IV launch vehicle with experimental data. The complete analysis process is then applied to the. H-II launch vehicle, the central rocket in japans space program, the CZ-3C launch vehicle developed in China and the KSR-III, a three-stage sounding rocket being developed in Korea. From the analyses, separation trajectories of strap-on boosters are predicted and aerodynamic characteristics around the vehicles at every time interval are examined. In addition, separation-impulse devices generally introduced for safe separation of strap-ons are properly modeled in the present paper and the jettisoning force requirements are examined quantitatively.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.57.4-58
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• 2015

Thanks to high cadence monitoring and high photometric accuracy of Korea Microlensing Telescope Network (KMTNet), we expect the detection of many events caused by wide-separation planets and free-floating planets, which is not easy due to the short event duration. Thus, it is important to understand wide-separation planetary lensing events. Several studies on the wide-separation events have been reported, but events caused by wide-separation planetary systems with a moon have not yet been studied. In this paper, we study the properties of events caused by planetary systems where wide-separation planets host a moon. We also study the effect of a finite background source star on the moon feature in the wide planetary-lensing events.

• Knowledge Management Research
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• v.15 no.4
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• pp.15-34
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• 2014

Creative problem solving has become an important issue in many fields. Among problems, dilemma need creative solutions. New creative and innovative problem solving strategies are required to handle the contradiction relations of the dilemma problems because most creative and innovative cases solved contradictions inherent in the dilemmas. Among various kinds of problem solving theories, TRIZ provides the concept of physical contradiction as a common problem solving principle in inventions and patents. In TRIZ, 4 separation principles solve the physical contradictions of given problems. The 4 separation principles are separation in time, separation in space, separation within a whole and its parts, and separation upon conditions. Despite this attention, an accurate definitions of the separation principles of TRIZ is missing from the literature. Thus, there have been several different interpretations about the separation principles of TRIZ. The different interpretations make problems more ambiguous to solve when the problem solvers apply the 4 separation principles. This research aims to fill the gap in several ways. First, this paper classify the types of contradiction relations and the contradiction solving dimensions based on the Butterfly model for contradiction solving. Second, this paper compares and analyzes each contradiction relation type with the Butterfly diagram. The contributions of this paper lies in reducing the problem space by recognizing the structures and the types of contradiction problems exactly.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.341-348
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• 2015

This paper addresses Monte-Carlo simulation analyses for the stage separation of the general launch vehicle. The stage separation event of the launch vehicle occurs during a very short time and is related with many dynamic parameters. The stage separation is a critical event in that the launch fails if there is a collision during the stage separation. The stage separation analyses was conducted for the general launch vehicle to confirm the separation without collision within the designed clearance in case of the random input parameters. This paper presents the stochastic results of the stage separation of the launch vehicle using the Monte-Carlo simulation.

• Journal of the Korean Institute of Rural Architecture
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• v.12 no.3
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• pp.35-46
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• 2010

The purpose of this study is to interpretate the Korean traditional Private Garden Pavilion -'byoul-seo(別墅)' in the view point of the architectural methodology - the separation of space in Honam province. It is presumed that nature union is archived through the 'yan-sang(玩賞)' which is ultimate state of knowledge that is base on the premises of opened signification in emancipation from narrow view point in the past and cognition of value. therefore, it is needed to know the unworldly point of space perception about the pavilion territory, furthermore to have conceptual method to distinct pavilion from the world. there are two methods in the distinct concept in this pavilion research: unworldly separation and meditative separation. As a result, the followings are conclusions; There two distinctive methods of planning of pavilion by use of the room and column. There are enclosement, turnaround, division of floor area in the room organization method, and it's modification of modulation, diversification of column height and diversification of column use in different space.

• ETRI Journal
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• v.38 no.1
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• pp.112-122
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• 2016

This paper presents a set of candidate regulatory requirements for TV band devices (TVBDs) in the Rep. of Korea. To guarantee the protection of incumbent services, especially digital TV (DTV) and wireless microphones, in TV frequency bands, we suggest minimum separation distances of TVBDs from the noise-limited contour according to incumbent users and TVBD types. This paper also deals with multiple sets of separation distances of a co-channel TVBD network from a DTV protected contour on the basis of the radio propagation characteristics of different geographic areas to make good use of TV white space (TVWS) and safely protect the DTV service. We present a low-power transmission mode of TVBDs and the relevant separation distances for small-cell deployment. The service coverage reduction ratio of a TVBD network is investigated in the presence of DTV interference in four geographic areas. The TVWS field verification results, conducted on the island of Jeju (Rep. of Korea), show that incumbent services operate well without harmful interference from neighboring TVBDs with the proposed separation distances.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.10
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• pp.827-832
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• 2013

Heating wire cutting type separation mechanism has been widely used for cube satellite applications due to its design constraints such as small size of $10cm{\times}10cm{\times}10cm$ and light weight of less than 1kg. In addition, usage of pyro technic device is not allowed for cube satellite application. The conventional methods have some disadvantages of relatively small mechanical constraint force and the system complexity for the multi-deployable systems. In this paper, a separation nut type non-explosive separation mechanism has been proposed and investigated. The effectiveness of the design has been verified through the qualification tests of the mechanism.

• Korean Institute of Interior Design Journal
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• v.14 no.3 s.50
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• pp.84-94
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• 2005

The purpose of this study is to establish the identity of the traditional residential space in Korea and Japan as analyzing the spatial characteristics and sociocultural roles of the 'in-between space' shown in their traditional dwelling space. Although they share culture area, it is meaningful to clarify the identity of both countries with many differences as the point of localization In globalization and the point of presenting the current and future directions of residential culture in both countries. Records and field studies have been carried out for the spatial characteristics and the sociocultural role focused on Ma-dang and Dae-chung in case of the 'in-between space' in Korean traditional dwellings and Inner housing, Doma, and Engawa in Japan. According to these findings, the spatial characteristics in common between Korea and Japan are open, half-open, separation, mitigation, integration, variation, continuation, hierarchy, mediation, and expansion. The 'in-between space', built by the separate Chae and Kan, of Korean traditional dwellings shows the separation by closed walls and the exclusive use by the fixed walls. In case of Japan, the integrated in-between space built by the separation of Kan shows open and connective tendencies and the variableness of walls has the tendency making ambiguous space with spatial softness. The sociocultural role of the 'in-between space' in Korean traditional dwelling space functions as the mitigation between the interior and exterior of the house as well as the male and female. Because the conception for protecting the private life is too weak, the sociocultural role of the 'in-between space' in Japanese traditional dwelling space seldom forms the space for an individual or the specific person among family. The space to welcome a guest functions as the mitigation between residents and outsiders as it is located in the inside of the private dwelling space.