• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.107-108
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• 2003

This study was conducted to investigate the effects of dilution rate and stored temperature of semen at 5, 25 and 35$^{\circ}C$ on fertility in liquid rooster semen. At 5$^{\circ}C$ cold temperature, no significant difference were found in sperm mobilities on dilution rate(1:1, 1:3, 1.6) among treatments. Sperm mobility for the conservation of 3 hours at 25∼35$^{\circ}C$ were significantly higher for 1:3 and 1:6 dilution rate(semen：diluent) groups than for 1:1 dilution rate group(P<0.05). In Fertility results after artificial insemination with the conservation of 3 hours at 5∼25$^{\circ}C$ temperature, no significant difference were found in fertility on dilution rate among treatments. Fertilities after artificial insemination with the conservation of 3 hours at 35$^{\circ}C$ were significantly higher for 1.3 and 1:6 dilution rate(semen：diluent) groups than for 1：1 dilution rate group(P<0.05).

• Journal of Trauma and Injury
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• v.31 no.3
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• pp.125-134
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• 2018

Purpose: The interest in the personal mobility started to grow and as the interest increases, there are growing concerns about the safety of it. The purpose of the study is to look at the types and dynamics of patients injured by the personal mobilities. Methods: This was a retrospective 2-year observational study, from January 2016 to December 2017, on the patients who visited the emergency center and the trauma center, with an injury related to driving the personal mobility. Cases of the personal mobility-related accident were collected based on electronic medical records and hospital emergency department-based injury in-depth surveillance data. Results: A total of 65 patients visited the emergency center and the trauma center, during this study period. Six patients of 50 adults admitted the alcohol consumption (12%) and two adult patients wore the helmet as the protection gear (3.1%). The number of the patients in 2017 rises three times more than the number of patients in 2016 (51 vs. 14). Injuries to the head and neck region (67.7%) was the most common, followed by the upper extremity (46.2%). Eleven patients (16.9%) were admitted to the hospital, of whom three were admitted to the intensive care unit due to intracranial hemorrhage. Nine patients underwent surgery. Conclusions: The use of the personal mobility will continue to grow and the accidents, caused by the vehicle, will increase along with it. The study showed the damage is worse than expected. Personal mobility currently has a limited safety laws and the riders are not yet fully aware of its danger. The improvement of the regulation of the personal mobility, safety education is needed.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.3
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• pp.59-66
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• 2019

In recent years, urban regeneration is focused on smart and pedestrian oriented development utilizing various mobility technology. The characteristics of walkways needs to reflect such development orientations. This research is the first step to find an adequate slope for ramp replacing stairs and shared by pedestrians, personal mobilities and powered wheelchairs. It aims to check if ramps on a recommended degree of angle by general guidelines are more preferred than stairs and find out what make difference of such preferences. Two surveys were conducted at $9^{\circ}$ and $9.6^{\circ}$ ramps coexisted with stairs at sequential and parallel location. The study on the survey result found that the general evaluation of $9^{\circ}$ ramp was better than $9.6^{\circ}$ ramp but $9^{\circ}$ ramp was not preferred than stairs while $9.6^{\circ}$ ramps was preferred. The difference of preferences was related to characteristics of stairs. The stair with shorter tread and riser next to $9^{\circ}$ ramp was evaluated much better than stairs next to $9.6^{\circ}$ ramp. Therefore the research concludes that $10.0^{\circ}$ which many guidelines recommend for the maximum slop of a ramp was not adequate for a ramp to replace stairs as a preferred means of vertical circulation. In addition the research found that the preference was sensitive to moving direction and gender especially in regards to comfort of stairs and safety of ramp. Most pedestrians chose a means of vertical circulation based on its comfort but pedestrian's evaluation of safety was most different based on moving direction.

• Journal of Adhesion and Interface
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• v.21 no.4
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• pp.129-134
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• 2020

Understanding charge trapping at the interface between conjugated semiconductor and polymer dielectric basically gives insight into the development of long-term stable organic field-effect transistors (OFET). Here, the charge transport properties of OFETs using polymer dielectric with various molecular weights (MWs) have been investigated. The conjugated semiconductor, pentacene exhibited morphology and crystallinity, insensitive to MWs of polymethyl methacrylate (PMMA) dielectric. Consequently, transfer curves and field-effect mobilities of as-prepared devices are independent of MWs. Under bias stress in humid environment, however, the drain current decay as well as transfer curve shift are found to increase as the MW of PMMA decreases (MW effect). The charge trapping induced by MW effect is irreversible, that is, the localized charges are difficult to be delocalized. The MW effect is caused by the variation in the density of polymer chain ends in the PMMA: the free volumes at the PMMA chain ends act as charge trap sites, corresponding to drain current decay depending on MWs of PMMA.

• PNF and Movement
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• v.10 no.1
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• pp.9-17
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• 2012

Purpose : This study's purpose is consideration about change of the hand grip strength according to different posture and shoulder flexion angle. The shoulder joint permits the greatest mobility and carries out the important function of stabilization for hand use. Hand grip activity is important to evaluate while assessing loads of shoulder in hand mobilities. Methods : Thirty(15 male, 15 female) college students with unknown shoulder dysfunction participated subject in five different positions of elbow extension with sitting and standing posture, different positions is followed : (1) shoulder $0^{\circ}$ flexion (2) shoulder $45^{\circ}$ flexion (3) shoulder $90^{\circ}$ flexion (4) shoulder $135^{\circ}$ flexion (5) shoulder $180^{\circ}$ flexion. Results : On the average, in the hand grip strength, the standing posture is higher than sitting posture. Sitting posture showed a most high level at the man's $0^{\circ}$ and woman's $135^{\circ}$. And standing posture showed a most high level at the man's $135^{\circ}$ and woman's $90^{\circ}$. Conclusion : The paired t-test was used to determine the different in grip strength between sitting and standing posture by shoulder angle change. There was no significant difference between the five position by sitting and standing posture. In man, correlation analysis revealed significant connection for all five position by sitting and standing posture. And in woman, correlation analysis revealed connection for all five position by sitting and standing posture.

• The Journal of Bigdata
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• v.5 no.2
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• pp.85-95
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• 2020

In this study, a mobility analysis method is suggested to estimate an O/D trip demand estimation using Mobile Phone Signaling Data. Using mobile data based on mobile base station location information, a trip chain database was established for each person and daily traffic patterns were analyzed. In addition, a new algorithm was developed to determine the traffic characteristics of their mobilities. To correct the ping pong handover problem of communication data itself, the methodology was developed and the criteria for stay time was set to distinguish pass by between stay within the influence area. The big-data based method is applied to analyze the mobility pattern in inter-regional trip and intra-regional trip in both of an urban area and a rural city. When comparing it with the results with traditional methods, it seems that the new methodology has a possibility to be applied to the national survey projects in the future.

• Current Photovoltaic Research
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• v.9 no.4
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• pp.145-159
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• 2021

Light soaking (LS) stability in polymer solar cells (PSCs) has always been a challenge to achieve due to unstable photoactive layer-electrode interface. Especially, the electron transport layer (ETL) and photoactive layer interface limits the LS stability of PSCs. Herein, we have modified the most commonly used and robust zinc oxide (ZnO) ETL-interface using an organic dye molecule and a co-adsorbent. Power conversion efficiencies have been slightly improved but when these PSCs were subjected to long term LS stability chamber, equipped with heat and humidity (45℃ and 85% relative humidity), an outstanding stability in the case of ZnO/dye+co-adsorbent ETL containing devices have been achieved. The enhanced LS stability occurred due to the suppressed interfacial defects and robust contact between the ZnO and photoactive layer. Current density as well as fill factors have been retained after LS with the modified ETL as compared to un-modified ETL, owing to their higher charge collection efficiencies which originated from higher electron mobilities. Moreover, the existence of less traps (as observed from light intensity-open circuit voltage measurements and dark currents at -2V) are also found to be one of the reasons for enhanced LS stability in the current study. We conclude that the mitigation ETL-surface traps using an organic dye with a co-adsorbent is an effective and robust approach to enhance the LS stability in PSCs.

• International Journal of Computer Science & Network Security
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• v.23 no.1
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• pp.153-163
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• 2023

This study is situated in the context of intelligent transport systems, where in-vehicle devices assist drivers to avoid accidents and therefore improve road safety. The vehicles present in a given area form an ad' hoc network of vehicles called vehicular ad' hoc network. In this type of network, the nodes are mobile vehicles and the messages exchanged are messages to warn about obstacles that may hinder the correct driving. Node mobilities make it impossible for inter-node communication to be end-to-end. Recognizing this characteristic has led to delay-tolerant vehicular networks. Embedded devices have small buffers (memory) to hold messages that a node needs to transmit when no other node is within its visibility range for transmission. The performance of a vehicular delay-tolerant network is closely tied to the successful management of the nodes' transit buffer. In this paper, we propose a message transit buffer management model for nodes in vehicular delay tolerant networks. This model consists in setting up, on the one hand, a policy of dropping messages from the buffer when the buffer is full and must receive a new message. This drop policy is based on the concept of intermediate node to destination, queues and priority class of service. It is also based on the properties of the message (size, weight, number of hops, number of replications, remaining time-to-live, etc.). On the other hand, the model defines the policy for selecting the message to be transmitted. The proposed model was evaluated with the ONE opportunistic network simulator based on a 4000m x 4000m area of downtown Bouaké in Côte d'Ivoire. The map data were imported using the Open Street Map tool. The results obtained show that our model improves the delivery ratio of security alert messages, reduces their delivery delay and network overload compared to the existing model. This improvement in communication within a network of vehicles can contribute to the improvement of road safety.

• International Area Studies Review
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• v.15 no.1
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• pp.267-288
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• 2011

As world trade becomes more active and expansive, job mobility has progressed correspondingly in growth. In particular, high-skilled scientists (including advanced-degree holders) now possess the option of various occupational and residential mobilities. We explain the "brain drain" by using two empirical examples. One concerns the U.S. experience of foreign-born Ph.D holders living and working in the United States. The other pertains to the Korean experience, where Korean-origin and foreign-born experienced scientists are actively recruited by the government. We also explore the necessary conditions for recruiting and keeping advanced-skilled scientists, the attainment of which will result in strong future economic growth.

• The Journal of the Acoustical Society of Korea
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• v.29 no.7
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• pp.448-457
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• 2010

Vibrations and wave propagations in waveguide structures can be analysed efficiently by using waveguide finite element (WFE) method. The WFE method only models the 2-dimensional cross-section of the waveguide with finite elements so that the size of the model and computing time are much less than those of the 3-dimensional FE models. For cylindrical shells or pipes which have simple cross-sections, the external coupling with fluids can be treated theoretically. For waveguides of complex cross-sectional geometries, however, numerical methods are required to deal with external fluids. In this numerical approach, the external fluid is modelled by the boundary elements (BEs) and connected to WFEs. In order to validate this WFE/BE method, a pipe submerged in water is considered in this study. The dispersion diagrams and point mobilities of the pipe simulated are compared to those that theoretically obtained. Also the acoustic powers radiated from the pipe are predicted and compared in both cases of air and water as an external medium.