• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.879-894
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• 2013

Recently, due to a explosive growth in the mobile Internet traffic, the problem of excessive data traffic handling on core network and thus scalability problem have been magnified in 3GPP LTE/SAE networks. Current LTE/SAE network based on the central P-GW (PDN Gateway) used as mobility anchor cannot deal with such demand for exponentially increasing mobile Internet traffic. In this paper, we propose a new LTE/SAE network architecture supporting distributed P-GWs and corresponding distributed mobility management to solve these problems. For this, in addition to the deployment of such distributed P-GWs, we propose a dynamic and distributed mobility management by distributing MMEs (Mobility Management Entities) which dynamically manages the location information of a UE's PDN connection, and also propose a handover procedure of such PDN connections by using the proposed distributed P-GWs and MMEs. The performance of the proposed dynamic and distributed LTE/SAE network system is compared with the current LTE/SAE network system in terms of handover latency and network throughput.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.593-601
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• 2001

In RC structure, sufficient anchorage of reinforcement is necessary for the member to produce the full strength. Generally, conventional standard hook is used for the reinforcement's anchorage. However, the use of standard hook results in steel congestion, making fabrication and construction difficult. Mechanical anchor offers a potential solution to these problems and may also ease fabrication, construction and concrete placement. In this paper, the required characteristics and the design considerations of mechanical anchor were studied. Also, the mechanical anchor was designed according to the requirements. To investigate the pull-out behavior and properness of mechanical anchorage, pull-out tests were performed. The parameters of tests were embedment length, diameter of reinforcement, concrete compressive strength, and spacing of reinforcements. The strengths of mechanical anchor were consistent with the predictions by CCD method. The slip between mechanical anchor and concrete could be controlled under 0.2mm. Therefore, the mechanical anchor with adequate embedment could be used for reinforcement's anchorage. However, it was observed that the strength of mechanical anchors with short spacing of reinforcements was greatly reduced. To apply the mechanical anchor in practice (e.g. anchorage of the beams reinforcements in beam-column joint), other effects that affect the mechanical anchor mechanism, such as confinement effect of adjacent member from frame action or effects of shear reinforcement, should be considered.

• Journal of The Korean Association For Science Education
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• v.33 no.1
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• pp.161-180
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• 2013

The purpose of this paper is to introduce the current studies and research methods about Learning Progressions disseminated to several countries including the U.S. since 2006. It also provides a methodological base to investigate learning progressions in science by introducing a case study of learning progression conducted in Korea. For this study, we described several features of current studies on learning progressions in the U.S., and reported the common ways and sequences employed in examining learning progressions especially with respect to assessment for learning. Learning progressions are descriptions of developmental pathways of learning a topic, in which science knowledge is used in students' engaging in science practices. Each learning progression consists of upper anchor, lower anchor, and intermediate steps that connect both anchors. In investigating a learning progression, researchers usually utilize Wilson's four building blocks of assessment system based on the assessment triangle. This kind of method was also applied in investigating the learning progression for water cycle in this study. We discussed implication and consideration for the future research on learning progressions in science in Korea.

• The Journal of Engineering Geology
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• v.21 no.3
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• pp.221-230
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• 2011

The movement of rock cut slopes may result in upheaval of an adjacent road. Because most cut slopes consist of rock, road upheaval due to the movement of a cut slope is a rare phenomenon in Korea. We found that the movement of rock slopes which are heavily weathered and with strongly developed weak zones is governed by circular failure of the overall rock formation rather than by failure along discontinuities. The results of a numerical analysis revealed that the application of a ubiquitous joint model in a continuum analysis is appropriate for anisotropic rocks (e.g., schist) and for slopes for which the stability is influenced by a particular discontinuity. The results of a field investigation and numerical analyses suggest that retaining walls and anchors should be used to stabilize rock slopes and that real-time monitoring equipment should be installed to assess the reinforcing effect of the remedial measures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.661-667
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• 2016

This study evaluated the potential of methodology development of the helical type anchor for soft ground applications. The rotational penetration of the helix structure might make construction-steps easy without the soil spitting and reusable rods could reduce the material cost. Removal of the anchors would be simple as a construction, which can be named the removal anchor. The anchoring resistance after construction is strongly related to the number of helixes resulting in a concise design process. The investigation involved a chamber test with soft soils. In the test, a specially designed and fabricated helical anchor and torque-driver were used to obtain the maximum pull-out resistance of the anchor after rotational penetration. As a result of the tests, The rotational torque and pull-out resistance have a proportional relationship with the strength of the prepared soils. Within the range of the study, the torque of the anchor penetrating increased with increasing pull-out resistance.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.17-26
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• 2008

In this study, the design method of slope reinforced by the earth retention systems were systematically developed, and the flow chart of design procedure fur each system were constructed to design the slope rationally. The proposed design method is composed of 5 steps such as field condition investigation step, slope design step, landslide occurrence prediction step, slope failure scale estimation step and reinforcement countermeasure selection step. The quantitative standard of slope failure scale was established based on the arrangement of various overseas standards which is estimating the slope failure, and the analysis of slope failure scale which is occurred in the country. The slope failure scale is classified into three categories the small scale of slope failure is less than $150m^3$ of slope failure volume, the middle scale of slope failure is from $150m^3$ to $900m^3$ and the large scale of slope failure is more than $900m^3$. The earth retention system could be selected by the proposed slope failure scale based on the slope failure volume. Meanwhile, the design methods of earth retention system such as piles, soil nails and anchors were developed. The optimal countermeasure for slope stability could be proposed using above design methods.

• Clinics in Shoulder and Elbow
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• v.10 no.1
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• pp.59-64
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• 2007

Purpose: The purpose of this study was to evaluate the results of bioabsorbable knotless suture anchoring for isolated type II SLAP. Materials and Methods: Fourteen patients with isolated type II SLAP underwent a surgical repair with bioabsorbable knotless anchor arthroscopically. Instability, rotator cuff tears or simple subacromial decompression were excluded. The UCLA and pain of VAS (Visual Analogue Scale), ADL (Activity of Daily Living, from the American Shoulder and Elbow Society) were evaluated and patients underwent a thorough shoulder examination at a minimum follow-up period of 2 years postoperatively. Results: At a mean of 27.1 months follow-up. The mean UCLA score improved from 14.4 pre-operatively to 31.2 on last follow-up. The mean VAS for pain was 4.9 and on last follow-up 1.0. The mean VAS for instability was 2.6 and on last follow-up 0.5. The mean ADL was 10.4 and on last follow-up 25.0. 12 patients reported their satisfaction as good to excellent and 10 of the 14 patients returned to their pre-injury level of activity (athletics) (P<0.05). Conclusion: Arthroscopic repair with bioabsorbable knotless suture anchors is an effective surgical technique for the treatment of an isolated unstable type II SLAP lesion. Overall satisfaction was only 85.7%. 1 patient had severe stiffness and 1 patient had shoulder pain.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.6
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• pp.569-579
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• 2016

In order to ensure the stability of tunnel portal slope, reinforcement method such as anchors, soil nails and rock bolts have been used in Korea. When selecting slope reinforcement methods in tunnel portal area such as reinforcement arrangement and length, trial and error method can be very time-consuming and it was also not easy to verify the selection of an optimum condition. In this study, using the FISH language embedded in the finite difference code FLAC3D program, the optimization technique was developed with the Differential Evolution Algorithm (DEA). After building a database on the soil nailing method in tunnel portal area, this system can be selected to an optimum arrangement plan based on the factor of safety through the FLAC3D analysis. Through the results of numerical analysis, it was confirmed that the number of analysis was decreased by about 8 times when DEA based optimization technique was used compared to the full combination (FC). In case of the design of slope reinforcement in tunnel portal area, if this built-system is used, it is expected that the selection of an optimum arrangement plan can be relatively easier.

• Journal of the Korean Arthroscopy Society
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• v.14 no.1
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• pp.49-52
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• 2010

Purpose: We introduce arthroscopically assisted mini-open rotator cuff repair using anterolateral approach. Operative Technique: Placing lateral decubitus position on general anesthesia, a standard arthroscopic glenohumeral examination is performed to evaluate lesions of shoulder joint through posterior and anterior portal. And then arthroscope is placed in the subacromial space and we evaluate the size of the torn tendon and perform arthroscopic acromioplasty through lateral portal. A 3 to 4 cm skin incision is performed from anterolateral edge of acromion to distal and dissected along to raphe between anterior and middle deltoid. A deltoid retractor is then placed, allowing direct visualization of the rotator cuff and humeral head. As torn tendon is tagged by traction suture, we try to anatomical reduction on the footprint and then perform single row or double row repair of the rotator cuff using suture anchors. To prevent avulsion of the deltoid from the acromion, additional sutures by bone tunnel with acromion and deltoid is performed. Conclusion: This technique is useful procedure to get direct approach to anterior portion of supraspinatus tendon and to need lesser deltoid retraction than portal extension approach due to dividing along to raphe between anterior and middle deltoid. Also it provide better visualization of the superior portion of subscapularis and infraspinatus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.293-300
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• 2018

The purpose of this study is to investigate the educational needs for career development according to the job type of nursing college students. In order to achieve the purpose of the study, 146 nursing college students from K and P universities in the Busan and Kyungnam areas were analyzed using a career anchor questionnaire. In addition, 28 nursing college students who showed a higher level of tendency among job types were selected and divided into 4 teams, and a focus group interview was conducted based on the contents of the created map. Its purpose is to investigate the educational needs of nursing college students to enhance their career development. First, the career anchor types of the nursing college students showed the highest score in the areas of lifestyle, security and stability, while the lowest types of career anchor were pure challenge and general managerial competence. Second, the educational needs for career development were categorized into four areas, namely major competence, practical competence, personality competence, and resource management competence. The major competences are nursing expertise and skills. The practical competences consisted of ward task management, communication, crisis coping ability and personality competence and these were divided into cooperation and responsibility recognition. The resource management competence consists of time management ability and stress management ability. The results of this study are meaningful in that they can be used as the basic educational data for the career development of nursing college students in the future. In addition, it is expected that they can be applied to the development of a curriculum for the improvement of nursing practice.