• Journal of the Korean Magnetics Society
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• v.14 no.6
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• pp.219-223
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• 2004

L $i_{0.5}$F $e_{2.5-{\chi}}$R $h_{\chi}$ $O_4$ ($\chi$ = 0.25, 0.50, 0.75, 1.00) has been prepared by solid state reaction. Crystallographic and magnetic properties were investigated by Mossbauer spectroscopy, SQUID magnetometry, and x-ray diffraction. The crystal structure is found to be a cubic spinel structure with space group Fd3m for all the samples. The lattice constant $a_{0}$ increases from 8.3365 $\AA$ to 8.3932 $\AA$ with increasing Rh concentration $\chi$. The migration of Li ion has been confirmed by x-ray patterns and the results of applied field Mossbauer analysis. The temperature dependence of the absorption area of each site was analyzed with the Debye model for the recoil-free fraction. The Debye temperature for the octahedral sites is almost as large as for the tetrahedral sites, thereby suggesting similar inter-atomic binding forces for the octahedral and the tetrahedral sites. The saturated magnetic moment and the Mossbauer spectra taken at 4.2 K under the applied field (6 T) show that the spin structure of L $i_{0.5}$F $e_{2.5-{\chi}}$R $h_{\chi}$ $O_4$ is compatible with the collinear Neel Model.

• Journal of Service Research and Studies
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• v.12 no.4
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• pp.1-18
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• 2022

This study was conducted to prove that the service philosophy is the development principle of human society in the service age. From ancient times to the present, the service philosophy was tried to show the wisdom of the development of human society in all earth spaces including the East and the West. In addition, it tried to prove that the service philosophy was at the center of the development wisdom of many countries and individuals who flickered on all space on earth and all human time. The study showed that the differences between countries were in software rather than hardware. Furthermore, it was analyzed that countries with a service philosophy embedded in the center of software such as spirit and culture made a great contribution to human society. The cases of Greece and Rome, the Republic of Venice, the Republic of the Netherlands, followed by the United States and modern Korea prove this, and the Soviet Union can be seen to disprove it. The former was a society in which state-run software was strong, and the latter was a society in which hardware was strong. There is a big difference between the case of the state, which citizens have autonomously organized and operated, and the case of the upper-level state-led operation. Since the leadership of the upper classes is not based on the service philosophy, the accumulated software power is weak, so it can be said that the accumulation of wisdom in human society is weak. Therefore, while the essence of human society so far has been a society of self-centered animal ecosystems led by selfishness, the human society in the service age from now on can be said to be a society of plant ecosystems where mutual respect and self-centeredness coexist. Just as the society centered on the service philosophy in the past human society prospered and left a greater legacy to mankind, it is suggested that the human society in the future service era should be a human society of a plant ecosystem centered on the service philosophy. Further in-depth studies related to this are needed in the future.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.2
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• pp.151-156
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• 2013

Hanwoo (Also known as Korean native cattle; Bos taurus coreanae) have been used for transportation and farming for a long time in South Korea. It has been about 30 yrs since Hanwoo improvement began in earnest as beef cattle for meat yield. The purpose of this study was to determine the trend of improvement as well as to estimate genetic parameters of the traits being used for seedstock selection based on the data collected from the past. Hanwoo proven bulls in South Korea are currently selected through performance and progeny tests. National Hanwoo genetic evaluations are implemented with yearling weight (YW), carcass weight (CW), eye muscle area (EMA), backfat thickness (BF) and marbling score (MS). Yearling weights and MS are used for selecting young bulls, and EMA, BF, and MS are used for selecting proven bulls. One individual per testing room was used for performance tests, and five individuals per room for progeny tests. Individuals tested were not allowed to graze pasture, but there was enough space for them to move around in the testing room. Feeds including roughages and minerals were fed ad libitum, and concentrates were provided at the rate of about 1.8% of individual weight. Overall means of the traits were $352.8{\pm}38.56$ kg, $335.09{\pm}44.61$ kg, $77.85{\pm}8.838\;cm^2$, $8.6{\pm}3.7$ mm and $3.293{\pm}1.648$ for YW, CW, EMA, BF and MS. Heritabilities estimated in this study were 0.30, 0.30, 0.42, 0.50 and 0.63 in YW, CW, EMA, BF and MS, respectively, which are similar to results from previous research. Yearling weight was 315.54 kg in 1998, and had increased to 355.06 kg in 2011, resulting in about 40 kg of improvement over 13 yrs. YW and CW have improved remarkably over the past 15 yrs. Breeding values between 1996 and 2000 decreased or did not change much, but have moved in a desirable direction since 2001. These improvements correspond with the substantial increase in use of animal models since the late 1990s in Korea. Hanwoo testing programs have practically contributed to the improvement in aspects of quality and quantity. In sum, the current selection system is good enough to accommodate circumstances where fewer sires are used on many more cows. Although progeny tests take longer and cost more, they seem to be appropriate under the circumstances of the domestic market with its higher requirement for better meat quality. Consequently, accumulative data collection, genetic evaluation model development, revision of selection indices, as well as cooperation among farms, associations, National Agricultural Cooperative Federation, universities, research institutes, and government agencies must be applied to the Hanwoo selection program. All these efforts will assist the domestic market to secure a competitive position against imported beef under Free Trade Agreement trade system and will provide farmers with higher profits as well as the public with a higher quality of beef.

• Tunnel and Underground Space
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• v.26 no.2
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• pp.59-67
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• 2016

In this paper, we perform a numerical analysis to evaluate the potential of fault reactivation during gas production from hydrate bearing sediments and the moment magnitude of induced seismicity. For the numerical analysis, sequential coupling of TOUGH+Hydrate and FLAC3D was used and the change in effective stress and consequent geomechanical deformation including fault reactivation was simulated by assuming that Mohr-Coulomb shear resistance criterion is valid. From the test production simulation of 30 days, we showed that pore pressure reduction as well as effective stress change hardly induces the fault reactivation in the vicinity of a production well. We also investigated the influence of stress state conditions to a fault reactivation, and showed that normal fault stress regime, where vertical stress is relatively greater than horizontal, may have the largest potential for the reactivation. We tested one simulation that earthquake can be induced during gas production and calculated the moment magnitude of the seismicity. Our calculation presented that all the magnitudes from the calculation were negative values, which indicates that induced earthquakes can be grouped into micro-seismic and as small as hardly perceived by human beings. However, it should be noted that the current simulation was carried out using the highly simplified geometric model and assumptions such that the further simulations for a scheduled test production and commercial scale production considering complex geometric conditions may produce different results.

• Tunnel and Underground Space
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• v.23 no.6
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• pp.480-492
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• 2013

After the introduction of geothermal power generation technology based on engineering reservoir creation that can be applied on non-volcanic region, industrial need for studies on the efficient and economic execution of costly deep-depth drilling work becomes manifest increasingly. However, since it is very difficult to predict duration and cost of boring work with acceptable reliability because of many uncertain events during the execution, efficient and organized work management for drilling is not easily achievable. Especially, the round trip that discretely occurs because of the abrasion of bit takes more time as the depth goes deeper and it has a great impact on the work performance. Therefore, a technology that can simulate the occurrence timing and depth of round trip in advance and therefore optimize them is essentially required. This study divided the abrasion state of bit into eight steps for simulation cases and developed a forecast algorithm, i.e., TOSA which can analyze the depth and timing of round trip occurrence. A methodology that can divide a unit section for simulation has been suggested; while the Bourgoyne and Young model has been used for the forecast of drilling rates and bit abrasion extent by section. Lastly, the designed algorithm has been systemized for the convenience of the user.

• Journal of the Korean Regional Science Association
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• v.33 no.1
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• pp.69-85
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• 2017

The positive changes in urban space and urban activities resulting from the urban services provided by Smart City is not accomplished by simply creating the physical environment built on ICT but through the cooperation and participation of citizens and private sector, which is in fact key to success. In this study, this research analyzed the role and structure of smart governance, which is a system of horizontal cooperation between public and private sector, and analyze its role in developing Smart City. The study also proposes various ways to facilitate such development in each of critical categories. For this purpose, this research studied 228 smart services across 11 categories registered in the Ministry of Land and Transport in Korea to analyze the spatial distribution of smart services by spatial hierarchy and their characteristics Also, the research conducted a case study of MetroGIS, which is an information collaboration governance system for the greater area of Minneapolis and St. Paul in the state of Minnesota, United States, to explore how governance is formed; its organizational structure; the role of sub-level organization hierarchy and their interrelationship. The results of the analysis suggest that the following conditions are required to create a smart city: first, public sector resource assistance for building community; second, enhanced communication system within the community and with outside the community; securing financial stability and establishing a model of sustainable development to induce the community to evolve into a governance form.

• The Korean Journal of Air & Space Law and Policy
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• v.34 no.1
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• pp.39-77
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• 2019

Crew members engaged in international air transportation provide work in many countries due to the nature of their work. According to the Private International Act, the place where the employee habitually carries out his/her work plays an important role in the determination of the governing law of the international labor contract (Article 28, Paragraph 2) and in the decision of international jurisdiction (Article 28, Paragraphs 3 and 4). The concept of the place where the employee habitually carries out his/her work was proposed by the EU to determine international jurisdiction and governing law. In international aviation law, the legislative purpose of the place where the employee habitually carries out his/her work is different from that of home base, which is a concept introduced for fatigue management of the crew in order to secure the aviation safety; thus the place where the employee habitually carries out his/her work and home base are not the same concept. In order to determine the place where the employee habitually carries out his/her work, following matters should be considered comprehensively; (i) where the crew starts and ends work, (ii) where the aircraft the crew is performing work on is primarily parked, (iii) where the crew is informed of the instructions and organizes his/her work activities, (iv) where the crew is obliged to reside according to the labor contract, (v) where there is an office provided by the employer and available to the crew, (vi) where the crew is obliged to be when he/she is ineligible for the work or subject to discipline. However, since all of the above items are the same as the location of the home base, it is reasonable to consider the home base as the most important factor when deciding on the place where the employee habitually carries out his/her work. In contrast, the state where the aircraft is registered (Article 17 of the Chicago Convention), should not be regarded as a place of where the employee habitually carries out his/her work. In this case, CJEU provided the first judging standard for the concept of the place where the employee engaged in international air transportation habitually carries out his/her work. It is the interpretation of the Brussels regulations which became a model -for the Korean Private International Act,- so it would be helpful to understand the concept of the place where the employee habitually carries out his/her work.

• Journal of the Korea Convergence Society
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• v.12 no.9
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• pp.113-120
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• 2021

As a result, the interaction between personal motivation and class type is not significant. On the other hand, the interaction between social motivation and class type is significant and overall online class increases engagement with educational issues. In particular, the group with low social motivation showed greater change than the group with high social motivation, so online education seems to be more effective in the group with low social motivation. It means that by stimulating students' social motivation rather than personal motivation, the effectiveness of online education can be enhanced, and it can lead to education outcomes - behavioral changes and attitudes of learners. In order to revitalize social motivation in the intensely personal space of online, it is necessary to activate social communication methods such as SNS, and development of interpersonal issues and learning materials would be more efficient. In order to derive more specific results, it is necessary to measure the level of prior knowledge and involvement of the participants in class, and to comprehensively investigate and analyze the state of learners before and after class through more variables. Finally, in order to increase the reliability of the research results, it is necessary to clearly prove it through the establishment of a structural model.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.47-50
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• 2007

[ $ZnCr_2O_4$ ] shows geometrically frustrated magnet. Recently, $CoCr_2O_4$ has been investigated for multiferroic property and dielectric anomalies by spin-current model. Polycrystalline $CoCr_2O_4$ and $CoCrFeO_4$ compounds was prepared by wet-chemical process. Crystallographic and magnetic properties of $CoCr_2O_4$ and $CoCrFeO_4$ were investigate by using the x-ray diffractometer(XRD), vibrating sample magnetometer(VSM), superconducting quantum interference device magnetometer(SQUID), and $M\"{o}ssbauer$ spectroscopy. The crystal structure was found to be single-phase cubic spinel with space group of Fd3m. The lattice constants of $CoCr_2O_4$ and $CoCrFeO_4$ $a_0$ were determined to be 8.340 and 8.377 ${\AA}$, respectively. The ferrimagnetic transition temperature for the both samples were observed at 97 K and 320 K. The $M\"{o}ssbauer$ absorption spectra at 4.2 K show that the well developed two sextets are superposed with small difference of hyperfine field($H_{hf1}=507\;and\;H_{hf2}=492\;kOe$). Isomer shift values($\delta$) of the two sextets are found to be 0.33 and 0.34 mm/s relative to the Fe metal, respectively, which are consistent with the high spin $Fe^{3+}$ charge state.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.70-81
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• 2024

In this study, Tridimensional Hybrid Isolation System(THIS) was proposed as a vibration isolator for traffic loads, combining vertical and horizontal isolation systems. Its efficacy in improving serviceability for vertical vibration was analytically evaluated. Firstly, for the analysis, the major vibration modes of the existing apartment were identified through eigenvalue analysis for the system and pulse response analysis for the bedroom slab using commercial structural analysis software. Subsequently, a 16-story model with horizontal, vertical and rotational degrees of freedom for each slab was numerically organized to represent the achieved modes. The dynamic analysis for the measured acceleration from an adjacent ground to high-speed railway was performed by state-space equations with the stiffness and damping ratio of THIS as variables. The result indicated that as the vertical period ratio increased, the threshold period ratio where the slab response started to be suppressed varied. Specifically, when the period ratio is greater than or equal to 5, the acceleration levels of all slabs decreased to approximately 70% or less compared to the non-isolated condition. On the other hand, it was ascertained that the influence of damping ratios on the response control of THIS is inconsequential in the analysis. Finally, the improvement in vertical vibration performance of THIS was evaluated according to design guidelines for floor vibration of AIJ, SCI and AISC. It was confirmed that, after the application of THIS, the residential performance criteria were met, whereas the non-isolated structure failed to satisfy them.