• Aerospace Engineering and Technology
• /
• v.13 no.1
• /
• pp.37-43
• /
• 2014

The ground station which operates the LEO satellite performs monitoring state of health of the satellite, sending the commands for the imaging mission of receiving the images during about 10 minutes of contact time. To finish the planned procedure in limited contact time, specific level of autonomy is applied in the satellite and the ground system. For example, the attitude and orbit control logic has high level of autonomy because it must be operated alone for long period without operator intervention. On the other hand, the fault management logic has relatively low level of autonomy because of that failure detection and safing operation are performed on-board, whereas failure identification and recovery are on-ground operation. The level of autonomy of the satellite affects also the ground operation. The command set for mission operation is generated by ground system. If the satellite has higher level of autonomy, some of operation currently done on-ground can be performed on-board, so the ground operation can be simplified. In this paper, we discuss the level of autonomy and propose a concept for improving the level of autonomy of an LEO satellite.

• Journal of Aerospace System Engineering
• /
• v.3 no.2
• /
• pp.31-38
• /
• 2009

COMS On-board FDIR(Failure Detection, Isolation and Recovery) functions are implemented on the on-board software to satisfy the autonomy and failure tolerance requirements. This paper presents concepts of COMS Failure Management with hierarchical layers and addresses the characteristics of the FDIR layer from low level to high level. It is aimed at giving the reader the understanding how the COMS FDIR was designed and how works. It first recalls what are the system level applicable requirements, which are based on the COMS mission requirements. Then it describes the philosophy and structure of the FDIR and subsequently breaks it down into the several FDIR layers. It could be used as an important and useful reference of the information to design and develop an automatic FDIR mechanism in the future.

• Journal of Satellite, Information and Communications
• /
• v.11 no.3
• /
• pp.51-57
• /
• 2016

Many kinds of telemetry should be monitored to check the state of spacecraft and it leads the time consumption. However, it is very important to define the status of satellite in short time because the contact number and time of low earth orbit satellite is limited. Also, on-board fault management should be prepared for non-contact operation because of the sever space environment. In this paper, on-board and ground autonomous operation method for the safety enhancement is described. Immediate fault detection and response is possible in ground by explicit anomaly detection through satellite event and error information. Also, satellite operation assistant system is proposed for ground autonomy that collect event sequence in accordance with related telemetry and recommend or execute an appropriate action for abnormal state. Critical parameter monitoring method with checking rate, mode and threshold is developed for on-board autonomous fault management. If the value exceeds the limit, pre-defined command sequence is executed.

• The Journal of the Korea Contents Association
• /
• v.7 no.4
• /
• pp.114-122
• /
• 2007

Recently, Game Rating Board has been established. It is to follow worldwide trend in building up publicity, autonomy and professionalism under the framework to assure freedom of expression. This article analyzed major nation's game rating system, and showed some points to need improvement which are to have more detailed classification in game rating, to modify contents descriptor, to appoint committee members with expertise on game, to revise articles to be capable of misuse, and to become a nongovernmental organization.

• Journal of dental hygiene science
• /
• v.19 no.1
• /
• pp.60-66
• /
• 2019

Background: This study aimed to provide basic data to establish a foundation for efficient operation of the organization by assessing the effects of self-efficacy and job stress (measured by self-efficacy, job demand, and job autonomy) on organizational commitment among clinical dental hygienists. Methods: This was a cross-sectional survey study that used a self-administered questionnaire to collect data. After institutional review board approval, a survey was conducted from January to May 2017, targeting dental hygienists working in dental clinics and hospitals. The final 199 questionnaires were analyzed with PASW 18.0 for Windows (IBM Corp.). The data were analyzed using mean and/or standard deviation t-test, one-way ANOVA, and multiple regression analysis. Results: The means for self-efficacy, job demand, job autonomy, and organizational commitment were $55.94{\pm}9.65$, $26.55{\pm}2.29$, $20.24{\pm}3.88$, and $49.49{\pm}8.39$, respectively. Along with self-efficacy, the other factors of organizational commitment among dental hygienists that were statistically significant included job autonomy, mean salary (2,500~2,990 thousand Korean won [KRW] and ${\geq}3,000$ thousand KRW), and employee welfare (good), which are sub-areas of the surface acting. In other words, it was found that the higher the mean salary, the better the employee welfare, the higher self-efficacy, and the higher the organizational commitment, and the explanatory power of the model was approximately 42.1%. Conclusion: These results suggest that the higher the self-efficacy, job autonomy, mean salary, and employee welfare, the higher the organizational commitment. In order to improve job demand among dental hygienists, it is necessary to establish an effective plan to improve job welfare, self-efficacy, and job autonomy.

• Journal of Korean Critical Care Nursing
• /
• v.8 no.1
• /
• pp.25-40
• /
• 2015

Purpose: The purpose of the study was to identify the frequency and importance of task performance and the perceived competence to perform of the emergency nurse practitioners (ENPs) certified in Korea. Method: This cross-sectional study was conducted with 41 ENPs certified by March 2012. The questionnaire to identify frequency, importance, autonomy, and perceived competence to perform 131 typical ENP task elements was developed on the basis of the standardized role of an ENP defined by the Korean Accreditation Board of Nursing Education. The data were analyzed using descriptive statistics. Results: The professional nursing practice showed the highest scores for performance frequency, task importance, autonomy, and perceived competence to perform as compared to other job categories. Clinical decision making was the most frequently performed duty. Data collection was the duty with highest levels of importance, autonomy, and perceived competence for the ENPs. However, the ENPs reported that research was the duty with the lowest levels of frequency, importance, autonomy, and perceived competence Conclusion: ENPs in Korea perform various tasks. In order to improve their position in the field, it is necessary to clarify their job description and enhance their competence to perform evidencebased professional nursing practices.

• Journal of Satellite, Information and Communications
• /
• v.9 no.4
• /
• pp.127-133
• /
• 2014

In this paper, we present the design, functions and performance analysis of the virtual machine (VM) based on the Lua interpreter for On-Board Control Procedure Execution Environment (OEE). The development of the OEE has been required in order to operate the lunar explorer mission autonomously which is planned by Korea Aerospace Research Institute (KARI) autonomously. The concept of On-Board Control Procedure (OBCP) is already being applied to the deep space missions with a long propagation delay and a limited data transmission capacity since it ensure he autonomy of the mission without the ground intervention. The interpreter is the execution engine in the VM and it interpreters high-level programming codes line by line and executes the VM instructions. So the execution speed is very more slower than that of natively compiled codes. In order to overcome it, we design and implement OEE using register-based Lua interpreter for execution engine in OEE. We present experimental results on a range of additional hardware configurations such as usages of cache and floating point unit. We expect those to utilized to the OBCP scheduling policy and the system with Lua interpreter.

• Journal of Astronomy and Space Sciences
• /
• v.38 no.1
• /
• pp.65-82
• /
• 2021

For the vast majority of geostationary satellites currently in orbit, station keeping activities including orbit determination and maneuver planning and execution are ground-directed and dependent on the availability of ground-based satellite control personnel and facilities. However, a requirement linked to satellite autonomy and survivability in cases of interrupted ground support is often one of the stipulated provisions on the satellite platform design. It is especially important for a geostationary military-purposed satellite to remain within its designated orbital window, in order to provide reliable uninterrupted telecommunications services, in the absence of ground-based resources due to warfare or other disasters. In this paper we investigate factors affecting the robustness of a geostationary satellite's orbit in terms of the maximum duration the satellite's station keeping window can be maintained without ground intervention. By comparing simulations of orbit evolution, given different initial conditions and operations strategies, a variation of parameters study has been performed and we have analyzed which factors the duration is most sensitive to. This also provides valuable insights into which factors may be worth controlling by a military or civilian geostationary satellite operator. Our simulations show that the most beneficial factor for maximizing the time a satellite will remain in the station keeping window is the operational practice of pre-emptively loading East-West station keeping maneuvers for automatic execution on board the satellite should ground control capability be lost. The second most beneficial factor is using short station keeping maneuver cycle durations.

• Journal of Arbitration Studies
• /
• v.17 no.2
• /
• pp.101-124
• /
• 2007

The legal systems and open-door policies to foreign affairs in North Korea have been followed by those of China. Whereas an arbitration system of South Korea accepted most parts of UNCITRAL Model Law, North Korea has succeeded to an arbitration system of a socialist country. China, under the arbitration system of socialist country, enacted an arbitration act reflected from UNCITRAL Model Law for keeping face with international trends. We have used these three arbitration system as a tool for analyzing an arbitration system in North Korea. With an open-door policy, North Korea and China enacted an arbitration act to provide a legal security. Therefore, the core parts of arbitration system in North Korea and China are based on a socialist system while those of South Korea is on liberalism. So, North Korea and China enacted an arbitration act on the basis of institutional arbitration, on the other side, South Korea is based on ad-hoc arbitration. Because of these characters, in terms of party autonomy, it is recognized with the order as South Korea, China and North Korea. Also North Korea enacted separate 'Foreign Economic Arbitration Act' to resolve disputes arising out of foreign economies including commercial things and investments. There are differences in arbitration procedures and appointment of arbitrators : South Korea recognizes parties' autonomy, however parties should follow the arbitration rules of arbitration institutes in North Korea and China. According to an appointment of arbitrators, if parties fail to appoint co-arbitrators or chief arbitrators by a mutual agreement, the court has the right to appoint them. In case of following KCAB's rules, KCAB secretariats take a scoring system by providing a list of candidates. A party has to appoint arbitrators out of the lists provided by arbitration board(or committee) in North Korea. If a party may fail to appoint a chief arbitrator, President of International Trade Arbitration Board(or Committee) may appoint it. In China, if parties fail to appoint a co-arbitrator or a chief arbitrator by a mutual agreement, Secretary general will decide it. If a arbitral tribunal fails to give a final award by a majority decision, a chief arbitrator has the right for a final decision making. These arbitration systems in North Korea and China are one of concerns that our companies take into account in conducting arbitration procedures inside China. It is only possible for a party to enforce a final arbitral award when he applies an arbitration inside North Korea according to International Trade Arbitration Act because North Korea has not joined the New York Convention. It's doubtful that a party might be treated very fairly in arbitration procedures in North Korea because International Trade Promotion Commission controls(or exercises its rights against) International Trade Arbitration Commission(or Board).

• Aerospace Engineering and Technology
• /
• v.8 no.2
• /
• pp.61-67
• /
• 2009

This paper proposes an on-board orbit data generation algorithm for geostationary satellites. The concept of the proposed algorithm is as follows. From the ground, the position and velocity deviations with respect to the assumed reference orbit are computed for 48 hours of time duration in 30 minutes interval, and the generated data are up-loaded to the satellite to be stored. From the table, three nearest data sets are selected to compute position and velocity deviation for asked epoch time by applying $2^{nd}$ order polynomial interpolation. The computed position and velocity deviation data are added to reference orbit to recover absolute orbit information. Here, the reference orbit is selected to be ideal geostationary orbit with a zero inclination and zero eccentricity. Thanks to very low computational burden, this algorithm allows us to generate orbit data at 1Hz or even higher. In order to support 48 hours autonomy, maximum 3K byte memory is required as orbit data storage. It is estimated that this additional memory requirement is acceptable for geostationary satellite application.