• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.106-114
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• 2017

In this paper, we propose the method of designing an extended kalman filter in order to accurately measure the position of the spatial-phase system using sensor fusion. We use the quaternion as a state variable in expressing the attitude of an object. Then, the attitude of rigid body can be calculated from the accelerometer and magnetometer by applying the Gauss-Newton method. We estimate the changes of state by using the measurements obtained from the gyroscope, the quaternion, and the vision informations by ARVR_SDK. To increase the accuracy of estimation, we designed and implemented the extended kalman filter, which showed excellent ability to adjust and compensate the sensor error. As a result, we could experimentally demonstrate that the reliability of the attitude estimation value can be significantly increased.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.15-22
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• 2012

The statistics of the safety accidents in labs show that the biggest reason for them is researchers' carelessness and insecure actions. In this way, the safety accidents in labs are affected a lot by researchers' safety consciousness. Therefore, in order to prevent the safety accidents in labs, this study aims at measuring the degree of researchers' safety consciousness, grasping the elements affecting their safety consciousness and suggesting the measures to improve the lacking safety consciousness. To accomplish this goal, a survey was conducted and analyzed on the safety consciousness of 1,226 researchers working at 10 government- supported research institutes in Daedeok R&D Complex. As a results, the measures to improve researchers' safety consciousness will be suggested as follows. First, in an environmental aspect, improvement of labs' environment exposed to danger, interest and participation of CEO, regular discussion on the safety in labs, installment of safety equipments in labs, and enlargement of individual labs are necessary. Second, in an educational aspect, the safety education offered by institutes need to be enhanced, experiential safety education fit for the characteristics of research should be applied, the time for safety education must be observed, and the communication among team members through the collective education in department units and safe culture through the campaigns to enhance safety consciousness have to be established. Third, in a systematic aspect, sanctions have to be imposed on the researchers who do not attend safety education, the number of safety supervisors and safety budget of labs should be increased, a safety certification system need to be introduced when a lab is built, the problems in safety have to be open to all departments and rewards for the persons of merit in labs should be extended.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.580-587
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• 2003

In this paper, we introduce a novel model to analyze the linearity of a TW-EAM (traveling-wave electroabsorption modulator). The device length, microwave loss (ML), and internal reflection (IR) due to impedance mismatch have effect on the linearity of a TW-EAM. The longer devices have characteristics of lower biases with minimum IMDS (intermodulation distortions). ML decreases the output power as well as the IMD value. Internal reflection has different nonlinear characteristics according to the wavelength of the input frequency and the device length. There is little change in SFDR (spurious-free dynamic range) due to ML or IR. As a result, for a 50 GHz band RF-optical communication system, a 0.8 mm-long TW-EAM with the lowest ML would have better properties by using n, which is caused by impedance, mismatch at the output port.

• Korean Journal of Materials Research
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• v.5 no.6
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• pp.650-656
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• 1995

High frequency SAW filters for cellular communications were fabricated by metallizing 36$^{\circ}$Y-X LiTaO$_3$piezoelectric substrate with IIDT type electrodes. It was found that the center frequency of the filter was lowered than as designed. In order to overcome such a drawback and enable a fine tuning of its center frequency, dielectric SiN$_{x}$ thin films were deposited on LiTaO$_3$substrate by PECVD as passivation layer and then frequency responses were also characterized. As a result, the center frequency of the filter could be shifted to a higher frequency with increasing the thickness of SiN$_{x}$ film, because SAW velocity increased with increasing the ratio of the thickness of dielectric thin film to wavelength. The insertion loss of the filter, however, became larger with increasing the thickness of SiN$_{x}$ film.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.30 no.4
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• pp.235-254
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• 2019

According to the development of information technology, the paradigm of the archives is shifting from preservation management of past records to use-oriented services. In this regard, this study is conducted an empirical study on the effect of internal marketing factors of university archives on the customer orientation of employees in order to improve organizational satisfaction for users of records information service. Based on the previous research, the delegation of authority, internal communication, management support, and training are established as factors of internal marketing, and the parameters for this are job satisfaction, organizational commitment, customer orientation as dependent variables, and We set up hypothesis between research variables and attempted an analysis through statistical system. In summary, each element of internal marketing showed significant results on job satisfaction and organizational commitment, and management support was most closely related to job satisfaction, organizational commitment, and customer orientation of university archive staff.

• Research in Community and Public Health Nursing
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• v.14 no.3
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• pp.488-495
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• 2003

Purpose: This study was attempted to provide the basic data in order to develop a supportive system for the family by investigation of the general and disability-related features of the industrial accident disabled and their family function. Method: Three hundred and forty six industrial accident disabled were randomly selected among those who resided in the Seoul, Incheon, and Gyeonggi areas, and who were confirmed as disabled according to its severity from the first to fourteenth grade from January, 1998 to December, 2000. The data were collected for one month from August 1 to August 31, 2001. Each study team consisted of two members out of 20 researchers and they interviewed the disabled individually by visiting their homes. Collected data were analyzed using frequency, percentages, t-test, ANOVA, and Correlation, etc. Results: The average score for family function was 102.60. The adaptability represented the highest score among the concepts dependent on the family function. The concepts were cohesion, adaptability and communication, which scored as 33.59, 35.38, 33.34, respectively. The family function was significantly different in education, marital status and subjective health status. In particular, the family function was excellent from the industrial accident disabled who had graduated from middle school, was married, and felt healthy. Depression and quality of life were other factors, which were also correlated significantly with the family function. The lower the degree of depression and the better the quality of life, the better the family function. Conclusion: The industrial accident disabled who had been in poor health or faced with difficulties in daily activities even after the therapy for the disability was completed. In particular, their family always had a great burden to care for the disabled and to take financial responsibility. Therefore, the rehabilitation program for the disabled should be family oriented.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.756-761
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• 2007

The construction Supply Chain Management(SCM) plays a critical role to proceed construction projects successfully. It is necessary to develop a system to support better communication among various actors and to supply construction materials in the right place on time with unstable situations on site according to the planned construction schedule for effective Supply Chain Management. Therefore, the objective of this study is to propose an automated and intelligent process that can be used to utilize ubiquitous technologies in construction supply chain management. This process consists of various equipments that can collect, store, calculate and communicate data among themselves. This study deals with a conceptual idea in order to improve process and equipment in the supply chain management process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.10
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• pp.851-860
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• 2013

To overcome a scarcity of radio resources to mobile broadband service, the usage of TV white space gains much attraction around the world. This paper carries out an interference analysis either by performing realistic experiments or by executing statistical Monte-Carlo simulation to exploit interference probability. The results obtained from experiments are compared to those from simulations in order to clarify the coexistence of utilization of TV band devices (TVBD) in indoor circumstances. Along the execution of our experiment in the presence of DTV receiver, we apply to a variety of transmission parameters proposed in FCC for TVBD. According to experimental and simulation works, the allowable transmission powers of TVBD systems are exploited for the plausible which are coexist on the first as well as the second adjacent frequency bands. Throughout results, it can conclude that TVBD systems can be coexisted via achieving proper transmission powers depending on the locations of themselves without showing harmful interference to DTV reception.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.211-218
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• 2000

This paper describes the improvement of broadband radio channel characteristics using a MMSE adaptive equalization technique as a fundamental study of high transmission rates in indoor radio channel. First, the performance of 16-QAM system that employs a MMSE linear adaptive equalizer in Rayleigh fading channel is analyzed. Next, in order to improve broadband radio channel characteristics, we apply an adaptive equalization technique employing the MMSE algorithm to the radio channel measured by using circularly polarized antenna under indoor NLOS(non-line-of sight) environment. Consequently, for 16-QAM with adaptive equalizer, we can achieve the improvement of about 13 dB at $10^{-3}$ error rate as compared with general 16-QAM. Moreover, it was found that the adaptive equalization technique could improve broadband radio channel characteristics over the all measured areas. Also, it was found that the employing both adaptive equalization and polarization diversity technique together could improve broadband radio channel characteristics and reduce fading more effectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2498-2504
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• 2009

This paper compared the output limit value of the Korean weak electric field strength wireless device in the 8.2MHz band with the standard values of foreign countries. Through this, the study confirmed that the Korean regulation was lower by about 10-20dB than those of the USA or Europe. In order to prove this, the study measured outputs by entrusting the 8.2MHz EAS system to two measuring companies. As a result of these measurements, electric field strengths were shown to be $70.6dB{\mu}V/m$ and $68.3dB{\mu}V/m$ respectively, and these values were confirmed to exceed the current Korean standard of $59.8dB{\mu}V/m$. Accordingly, it is deemed necessary to review the specifications of the Korean standard in the 8.2MHz band.