• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.1
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• pp.63-71
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• 2018

In this study, the torque and horizontal stress acting on vane were measured and then used to determine a friction angle of sand. A dry Nakdong River sand was prepared for loose and dense conditions in a cell and then pressurized with 25, 50, 75 or 100 kPa from the surface of sand. A vane (5cm in diameter and 10cm in height) was rotated and the torque and horizontal stress were measured at real time. A maximum torque was 3.5-9.5Nm for loose sand and 7.4-17.6Nm for dense sand, respectively. The maximum torque increased as an overburden pressure increased. The maximum torque obtained at 14-20 degrees of vane rotation, which was not influenced by the initial alignment of earth pressure and vane blade. An initial horizontal stress ratio was 0.33-0.35 on the average. The horizontal stress increased initially and then decreased due to particle disturbance. A friction angle was calculated from real time varying horizontal stress and torque, which decreased with increasing overburden pressure. The friction angle of loose sand from vane shear test was similar to that of direct shear test but that of dense sand was overestimated.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.96-110
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• 2018

As the development of ICT has made it easier to collect various traffic information, research on creating new traffic attributes is drawing attention. Estimation and forecasts of demand and traffic volume are one of the main indicators that are essential to traffic operation, assuming that the traffic pattern at a particular node or link is repeated. Traditionally, a survey method was used to demonstrate this similarity on trip behavior. However, the method was limited to achieving high accuracy with high costs and responses that relied on the respondents' memory. Recently, as traffic data has become easier to gather through ETC system, smart card, studies are performed to identify the regularity of trip in various ways. In, this study, route-level trip data collected in Daegu metropolitan city were analyzed to confirm that individual traveler forms a spatially similar trip chain over several days. For this purpose, we newly define the concept of spatial trip regularity and assess the spatial difference between daily trip chains using the sequence alignment algorithm, Dynamic Time Warping. In addition, we will discuss the applications as the indicators of fixed traffic demand and transportation services.

• Journal of the Korean Geotechnical Society
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• v.24 no.8
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• pp.25-34
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• 2008

A new hybrid oedometer cell is designed and manufactured to investigate a behavior of soft soils by using elastic and electromagnetic waves during consolidation test. Bender elements, which generate and detect shear waves, are placed in the top cap and the bottom plate and mounted on the oedometer wall. Double wedge type electrical resistance probe, which measures local void ratio change, is positioned onto the top cap of the oedometer cell. The bender elements and the electrical resistance probe are anchored into a nylon set screw with epoxy resin. The nylon set screw with epoxy resin minimizes directly transmited elastic waves through the oedometer cell due to impedence mismatch and allows for easy replacement of defected bender elements and electrical resistance probe. Primary consolidation time can be estimated from the slope of electrical resistance versus log time curve and the evolution of shear wave velocity. The shear wave velocity can be used to assess inherent anisotropy when disturbance effects are minimized because particle alignment affects the shear wave velocity. The void ratios evaluated by the electrical resistance probe are similar to those by the settlement during consolidation. This study suggests that the shear wave velocity and the electrical resistance can provide complementary imformations to understand consolidation characteristics such as primary consolidation, anisotropy, and void ratio.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.93-104
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• 2024

Facility diagnosis is essential for the smooth operation and life extension of rotating equipment used in industrial sites. Compared to other diagnostic methods, vibration diagnosis can find most of the initial defects, such as unbalance, alignment failure, bearing defects and resonance, compared to other diagnostic methods. Therefore, vibration analysis is the most commonly used facility diagnosis method in industrial sites, and is usefully used as a predictive preservation (PdM) technology to manage the condition of the facility. However, since the vibration diagnosis method is performed based on experience based on the standard, it is carried out by experts. Therefore, it is intended to contribute to the reliability of the facility by establishing a system that anyone can easily judge defects by establishing a vibration diagnosis method performed based on experience as a knowledgeable code system. An algorithm was developed based on the ISO-20816 standard for vibration measurement, and the reliability was verified by comparing the results of vibration measurement at various demonstration sites such as petrochemical plant compressors, hydrogen charging stations, and industrial machinery with the results of analysis using a development system. The developed algorithm can contribute to predictive maintenance (PdM) technology that anyone can diagnose the condition of the rotating machine at industrial sites and identify defects early to replace parts at the exact time of replacement. Furthermore, it is expected that it will contribute to reducing maintenance costs and downtime due to the failure of rotating machines when applied to various industrial sites such as oil refining facilities, transportation, production facilities, and aviation facilities.

• Journal of the Korean Arthroscopy Society
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• v.6 no.2
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• pp.101-108
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• 2002

Purpose: To evaluate the clinical results of anterior cruciate ligament (ACL) reconstruction and to know the results of physeal injury by transphyseal tunnel in adolescents who had remaining growth potential. Materials and Methods : This study involved 12 patients under 19 years old out of 445 patients, who underwent ACL reconstruction between 1993 and 2001. The mean age at the time of operation was 15.9 $(13.1\~16.9)$ years and fellow-up period was 45.1 $(24\~120.6)$ months in avrarge. Autologous quadrupled hamstring tendon was used as graft in 11 cases and bone-patellar tendon-bone in 1 case. Clinical results were evaluated by Lysholm Knee Scoring Scale, range of motion and return to preinjury sports activities. Radiologic results were evaluated by $Telos^{\circledR}$ device. Bone maturity were analyzed by chronological age, standing height and the width of growth plate in AP and lateral view of knee joint at preoperatively. The growth disturbances were evaluated by measuring femorotibial angle, anatomical and mechanical lateral distal femoral angle, mechanical medial proximal tibial angle and leg length and by comparing those of uninjured site in last follow-up teleoroentgenogram. Results : The mean Lysholm Knee score was 51 $(25\~63)$points preoperatively and 98 $(94\~100)$ points at last follow up. The mean anterior displacement of the tibia by using $Telos^{\circledR}$ device was improved from 13.5 $(6\~27)$ mm to 2.9 $(1\~4)$ mm and there were no significant instabilities of the knee in all cases. There were no leg length discrepancies over 1 cm and no statistically significant abnormal alignment of the knee joint in all cases. Conclusion: ACL reconstruction using transphyseal tunnel for restoring stability and knee function is assumed as a good mettled of treatment without significant leg length discrepancy and abnormal alignment of the knee joint.

• Asia pacific journal of information systems
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• v.19 no.3
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• pp.99-124
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• 2009

Many firms in Korea have adopted and used advanced information technology in an effort to boost efficiency. The process of adapting to the new technology, at the same time, can vary from one firm to another. As such, this research focuses on several relevant factors, especially the roles of social interaction as a key variable that influences the technology adaptation process and the outcomes. Thus far, how a firm goes through the adaptation process to the new technology has not been yet fully explored. Previous studies on changes undergone by a firm or an organization due to information technology have been pursued from various theoretical points of views, evolved from technological and institutional views to an integrated social technology views. The technology adaptation process has been understood to be something that evolves over time and has been regarded as cycles between misalignments and alignments, gradually approaching the stable aligned state. The adaptation process of the new technology was defined as "appropriation" process according to Poole and DeSanctis (1994). They suggested that this process is not automatically determined by the technology design itself. Rather, people actively select how technology structures should be used; accordingly, adoption practices vary. But concepts of the appropriation process in these studies are not accurate while suggested propositions are not clear enough to apply in practice. Furthermore, these studies do not substantially suggest which factors are changed during the appropriation process and what should be done to bring about effective outcomes. Therefore, research objectives of this study lie in finding causes for the difference in ways in which advanced information technology has been used and adopted among organizations. The study also aims to explore how a firm's interaction with social as well as technological factors affects differently in resulting organizational changes. Detail objectives of this study are as follows. First, this paper primarily focuses on the appropriation process of advanced information technology in the long run, and we look into reasons for the diverse types of the usage. Second, this study is to categorize each phases in the appropriation process and make clear what changes occur and how they are evolved during each phase. Third, this study is to suggest the guidelines to determine which strategies are needed in an individual, group and organizational level. For this, a substantially grounded theory that can be applied to organizational practice has been developed from a longitudinal comparative case study. For these objectives, the technology appropriation process was explored based on Structuration Theory by Giddens (1984), Orlikoski and Robey (1991) and Adaptive Structuration Theory by Poole and DeSanctis (1994), which are examples of social technology views on organizational change by technology. Data have been obtained from interviews, observations of medical treatment task, and questionnaires administered to group members who use the technology. Data coding was executed in three steps following the grounded theory approach. First of all, concepts and categories were developed from interviews and observation data in open coding. Next, in axial coding, we related categories to subcategorize along the lines of their properties and dimensions through the paradigm model. Finally, the grounded theory about the appropriation process was developed through the conditional/consequential matrix in selective coding. In this study eight hypotheses about the adaptation process have been clearly articulated. Also, we found that the appropriation process involves through three phases, namely, "direct appropriation," "cooperate with related structures," and "interpret and make judgments." The higher phases of appropriation move, the more users represent various types of instrumental use and attitude. Moreover, the previous structures like "knowledge and experience," "belief that other members know and accept the use of technology," "horizontal communication," and "embodiment of opinion collection process" are evolved to higher degrees in their dimensions of property. Furthermore, users continuously create new spirits and structures, while removing some of the previous ones at the same time. Thus, from longitudinal view, faithful and unfaithful appropriation methods appear recursively, but gradually faithful appropriation takes over the other. In other words, the concept of spirits and structures has been changed in the adaptation process over time for the purpose of alignment between the task and other structures. These findings call for a revised or extended model of structural adaptation in IS (Information Systems) literature now that the vague adaptation process in previous studies has been clarified through the in-depth qualitative study, identifying each phrase with accuracy. In addition, based on these results some guidelines can be set up to help determine which strategies are needed in an individual, group, and organizational level for the purpose of effective technology appropriation. In practice, managers can focus on the changes of spirits and elevation of the structural dimension to achieve effective technology use.

• The KIPS Transactions:PartB
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• v.15B no.4
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• pp.275-284
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• 2008

With increases in recent security requirements, biometric technology such as fingerprints, faces and iris recognitions have been widely used in many applications including door access control, personal authentication for computers, internet banking, automatic teller machines and border-crossing controls. Finger vein recognition uses the unique patterns of finger veins in order to identify individuals at a high level of accuracy. This paper proposes new device and methods for touchless finger vein recognition. This research presents the following five advantages compared to previous works. First, by using a minimal guiding structure for the finger tip, side and the back of finger, we were able to obtain touchless finger vein images without causing much inconvenience to user. Second, by using a hot mirror, which was slanted at the angle of 45 degrees in front of the camera, we were able to reduce the depth of the capturing device. Consequently, it would be possible to use the device in many applications having size limitations such as mobile phones. Third, we used the holistic texture information of the finger veins based on a LBP (Local Binary Pattern) without needing to extract accurate finger vein regions. By using this method, we were able to reduce the effect of non-uniform illumination including shaded and highly saturated areas. Fourth, we enhanced recognition performance by excluding non-finger vein regions. Fifth, when matching the extracted finger vein code with the enrolled one, by using the bit-shift in both the horizontal and vertical directions, we could reduce the authentic variations caused by the translation and rotation of finger. Experimental results showed that the EER (Equal Error Rate) was 0.07423% and the total processing time was 91.4ms.

• Economic and Environmental Geology
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• v.6 no.4
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• pp.201-216
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• 1973

Being believed thus far to be distributed in the wide areas in the vicinity of Seoul, the capital city of Korea, the Yonchon System in its type locality in Yonchon-gun from which the name derived was never previously traced down or correlated to the Precambrian metamorphic complex in Seoul area where the present study was carried out. Due to in accessibility to Yonchon area, the writer also could not trace the system down to the area studied so as to correlate them. The present study endeavored to differentiate general stratigraphy and interprete the structure of the metamorphic complex in the area. In spite of the complexity of structure and rapid changes in lithofacies of the complex, it was succeeded to find out the key bed by which the stratigraphy and structure of the area could be straightened out. The keybeds were the Buchon limestone bed in the western parts of the area; Daisongri quartzite bed cropped out in the southeastern area; Jangrak quartzite bed scattered in the several localities in the northwest, southwest, and eastern parts of the area; and Earn quartzite bed isolated in the eastern part of the area. These keybeds together with the broad regional structure made it possible to differentiated the Precambrian rocks in ascending order into the Kyonggi metamorphic complex, Jangrak group and Chunsung group which are in clinounconformable relation, and the first complex were again separated in ascending order into Buchon, Sihung, and Yangpyong metermorphic groups. Althcugh it has being vaguely called as the Yonchon system thus far, the Kyonggi metamorphic complex have never been studied before. The complex might, however, belong to early to early-middle Precambrian age. The Jangrak and Chunsung group were correlated to the Sangwon system in North Korea by the writer (1972), but it became apparent that the rocks of the groups have different lithology and highly metamorphosd than those of the Sangwon system which has thick sequence of limestone and slightly metamorphosed. Being deposited in the margin of the basin, it is natural that the groups poccess terrestrial sediments rather than limestone, yet no explanation is at hand as to what was the cause of bringing such difference in grade of metamorphism. Thus the writer attempted to correlate the both groups to those of pre-Sangwon and post-Yonchon which might be middle to early-late Precambrian time. Judging from difference in grade of deformation and unconformity between the Kyonggi metamorphic complex, Jangrak group, and Chunsung group, three stages of orogeny were established: the Kyonggi, Jangrak orogenies, and Chunsung disturbance toward younger age. It is rather astonishing to point out that the structure of these Precambrian formations. was not effected by Daebo orogeny of Jurassic age. The post-tectonic block faulting was accompanied by these orogenies, and in consequence NNE and N-S trending faults were originated. These faulting were intermittented and repeated until Daebo orogeny at which granites intruded along these faults. The manifestation of alignment of these faults is indicated by the parallel and straight linear development of valleys and streams in the Kyonggi Massifland.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.1-13
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• 2012

This study aims to analyze actual conditions of the present national defense information network operation, the structure and management of the system, communication lines, security equipments for the lines, the management of network and software, stored data and transferred data and even general vulnerable factors of our army tactical C4I system. Out of them, by carrying out an extensive analysis of the army tactical C4I system, likely to be the core of future information warfare, this study suggested plans adaptive to better information security, based on the vulnerable factors provided. Firstly, by suggesting various information security factor technologies, such as VPN (virtual private network), IPDS (intrusion prevention & detection system) and firewall system against virus and malicious software as well as security operation systems and validation programs, this study provided plans to improve the network, hardware (computer security), communication lines (communication security). Secondly, to prepare against hacking warfare which has been a social issue recently, this study suggested plans to establish countermeasures to increase the efficiency of the army tactical C4I system by investigating possible threats through an analysis of hacking techniques. Thirdly, to establish a more rational and efficient national defense information security system, this study provided a foundation by suggesting several priority factors, such as information security-related institutions and regulations and organization alignment and supplementation. On the basis of the results above, this study came to the following conclusion. To establish a successful information security system, it is essential to compose and operate an efficient 'Integrated Security System' that can detect and promptly cope with intrusion behaviors in real time through various different-type security systems and sustain the component information properly by analyzing intrusion-related information.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.45-54
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• 2009

Despite vehicle instability problems caused by gusts of wind on freeways located in mountain or seaside areas, current national highway design standards overlook their detrimental effects, and if higher design speed freeways being proposed now by the government are in operation, the strong effect of the gust of wind becomes a highway alignment design issue. This paper presents the vehicle movements and their resulting safety effects by checking vehicle sliding and overturn based on vehicle dynamic analysis for the case when a gust of wind blows to vehicles negotiating curves on higher speed freeways. In this analysis, vehicle types, curve radii, motorist responsive time to vehicle driving path changes, and vehicle speeds are systematically arranged to get vehicle sliding and overturn values in each different conditions. The results showed that there were little overturn possibilities when wind speed would stay in 50m/sec with higher than 600 meter curve radii. Interestingly it was also found in sliding checks that, although being safe at less than 15.0m/sec wind speed levels, there appeared the need of vehicle travel prohibitions when the wind speed could exceed 25.0m/sec level. The findings in this research is of information in future higher speed freeway designs, and particularly useful when designing freeways passing frequent gust wind areas.