• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12A
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• pp.971-981
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• 2009

The coordination of distributed entities and events requires time synchronization. Precision time synchronization enables a variety of extensions of applications and provides much accurate information. The IEEE 1588 precision time protocol (PTP) provides a standard method to synchronize devices in a network. This paper deals with the design and implementation of a PTP gateway to extend IEEE 1588 to Zigbee networks. The PTP gateway can not only extend IEEE 1588 to Zigbee networks but also share the same time reference using IEEE 1588 between two or more Zigbee networks. This paper also presents experiments and performance evaluation of time synchronization using the PTP gateway. Our result established a method for nodes in a network to maintain their clocks to within a 300 nanosecond offset from the reference clock of a master node via Ethernet.

• Journal of Educational Research in Mathematics
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• v.25 no.2
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• pp.225-240
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• 2015

In this study, we investigated the representativeness of proofs in school mathematics, based on the extension of the midpoint connector theorem for the quadrilateral. To this end, we considered a variety of quadrilateral and proved their extensions of the midpoint connector theorem, and identified the relationships between them, therefore seemed that the proof in school mathematics has a representativeness. On the other hand, in the survey based on this information, students were found only some types of quadrilateral and completed easily the proofs for each quadrilateral they found, but students tended to use other proof or mathematical concepts, if the target figures changes in despite of proving the same mathematical fact. Thus, students were more difficult to figure out the relationship between the proofs. From these facts, we know that students are poorly understood the representativeness of proofs to understand the relationship between concrete proofs and to generalize it, though they are able to proof to the specific figures. Therefore it can be seen that the proof activity needs to be done with organic and semantic.

• Computational Structural Engineering
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• v.4 no.2
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• pp.87-94
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• 1991

In this paper, a mixed variational principle applicable to the linear elasticity of inhomogeneous anisotropic materials is presented. For derivation of the general variational principle, a systematic procedure for the variational formulation of linear coupled boundary value problems developed by Sandhu et al. is employed. Consistency condition of the field operators with the boundary operators results in explicit inclusion of boundary conditions in the governing functional. Extensions of admissible state function spaces and specialization to a certain relation in the general governing functional lead to the desired mixed variational principle. In the physical sense, the present variational principle is analogous to the Reissner's recent formulation obtained by applying Lagrange multiplier technique followed by partial Legendre transform to the classical minimum potential energy principle. However, the present one is more advantageous for the application to the general anisotropic materials since Reissner's principle contains an implicit function which is not easily converted to an explicit form.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.66-77
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• 2009

In this paper, we propose a CORBA middleware extension which is suitable to SCA based communication environment. The extensions guarantee the components to interconnect others without consideration about its implementation way and enables the developers to easily achieve the performance improvements in comparison to the existing methodology. This extension includes the HAO, the IDL2VHDL compiler, and the improvement of ORBit. The HAO is ORB implemented in logic level and is limited the some function according to the characteristic of FPGA. In addition, the IDL2VHDL compiler provides the mapping from CORBA IDL to VHDL, the VHSIC hardware description language, and the additional procedures for processing the component. Finally, the improved ORBit, CORBA ORB on GPP, can be direct connecting with the HAO on FPGA.

• Journal of Agricultural Extension & Community Development
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• v.21 no.2
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• pp.211-254
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• 2014

Malawi's agricultural extension system has been subjected to a number of criticisms in recent times for failing to contribute significantly to agricultural development and for not responding to the needs of the smallholder farmers. Despite this, extension is still seen as key to improving poverty and rural livelihoods.There is a number of challenges facing extension that require a response from the public sector and other stakeholders. A clear and positive response to these challenges will help shape the future of agricultural extension in Malawi for the benefit of all farmers and the attainment of the broad policy objectives of government: democratization, market liberalization, decentralization, HIV/AIDS crisis, shrinking public sector resources, public sector reform, and co-ordination, etc. The mission is to provide pluralistic demand driven extensions services and promote equalisation and co-ordination in service provision in order to achieve food security at household level, there-by reducing poverty. On the other hand the vision is that 'All farmers' demand and access high quality extension services from those best able to provide them'. DAES implements its extension policy through the District Agricultural Extension Services System (DAESS), based on Model Village Approach.

• Physical Therapy Korea
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• v.12 no.2
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• pp.11-19
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• 2005

Patellofemoral pain syndrome (PFPS) is often attributed to malalignment and maltracking of patella within the patellofemoral joint. Most exercise for PFPS has focused on selectively strengthening the vastus medialis oblique muscle (VMO). This study was designed to identify the effect of medial, lateral wedge and difference of Quadriceps angle (Q-angle) on vastus medialis oblique/vastus lateralis muscle (VL) activity ratios. The subjects were twenty young adult males who had not experienced any knee injury. They were asked to perform isometric contraction exercises in three postures using medial and lateral wedge. The EMG activity of the VL and VMO were recorded in three postures by surface electrodes and normalized by %MVC values derived from seated, isometric knee extensions. The normalized EMG activity levels (%MVC) of the VL and VMO for the three postures of the lower extremities were compared using 2-way repeated measures ANOVA with 1 between-subject factor (group), and 1 within-subject factor (wedge). Results of repeated measures of ANOVA's revealed that the medial wedge isometric contraction exercise produced significantly greater EMG activity of VMO/VL ratios in Group I (Q-angle $18^{\circ}$ or less) (p<.05). But, the medial wedge isometric contraction exercise was no significant difference of VMO/VL ratios in Group II (Q-angle $19^{\circ}$ or more) (p>.05). These results have important implications for selective VMO muscle strengthening exercises in PFPS patients.

• Physical Therapy Korea
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• v.11 no.3
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• pp.1-9
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• 2004

Most exercise for Patellofemoral pain syndrome (PFPS) has focused on selectively strengthening the vastus medialis oblique muscle (VMO). Although open chain knee extension exercises are effective for increasing overall quadriceps strength, they are not always indicated for PFPS rehabilitation. This study was designed to identify the effect of combined posture of lower extremity on Electromyographic (EMG) activity of the vastus lateralis muscle (VL) and VMO during static squat exercises. The subjects were twenty young adult males who had not experienced any knee injury and their Q-angle was within a normal range. They were asked to perform static squat exercises in five various postures using their lower extremities. The EMG activity of the VL and VMO were recorded in five exercises by surface electrodes and normalized by %MVC values derived from seated, isometric knee extensions. The normalized EMG activity levels (%MVC) of the VL and VMO for the five postures of the lower extremities were compared using one way ANOVA with repeated measures. Results of repeated measures of ANOVA's revealed that exercise 3 and exercise 5 produced significantly greater EMG activity of VMO/VL ratios than exercise 1 (p<.05). When the static squat exercise was combined with hip adduction and toes pointed outwardly, the EMG activity of VMO/VL rates was increased. The EMG activity of VMO/VL ratio was highest during static squat exercises performed on a decline squat. These results haveimportant implications for progressive and selective VMO muscle strengthening exercises in PFPS patients.

• Physical Therapy Korea
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• v.18 no.3
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• pp.1-7
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• 2011

The effects of an abdominal drawing-in maneuver (ADIM) using a pressure bio-feedback unit (PBFU) were compared to the effects of a pelvic belt (PB) on the muscle activities of the hip and back extensor muscles during hip extension in the prone position. Fifteen healthy male participants all performed prone hip extensions under three conditions: 1) preferred hip extension (PHE), 2) performing an ADIM, and 3) using a PB. The muscle activities of the erector spinae, the gluteus maximus, and the medial hamstring on the right side were recorded by surface electromyography. The muscle activity of the erector spinae was significantly lower while performing an ADIM during prone hip extension than during PHE or with a PB (p<.05). Gluteus maximus muscle activity was significantly higher while performing an ADIM (p<.05). No significant difference was found for the medial hamstring muscle among the three conditions (p>.05). We concluded that the internal stabilization of the pelvis and lumbar spine afforded by the ADIM using a PBFU could be more effective than the external stabilization provided by a PB in terms of increasing selectively gluteus maximus activation during prone hip extension.

• Journal of Digital Convergence
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• v.13 no.6
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• pp.267-273
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• 2015

Recently, a wide range of products incorporating cutting-edge technology are being introduced in various sectors of design. Belkin's WeMo or Phillips' Hue are representative examples. In this context, the color-responsive lighting bookcase is a design product that would satisfy the needs of contemporary consumers who seek entertainment in their purchases. By installing lightings that change color according to the user's behavior, this design reconceptualizes the bookcase as a source of entertainment rather than a mundane object of household furnishing. The lighting apparatus can be detached and reattached, serving as stand-alone equipment. The lighting bookcase is modularized, comprising extensions equipped with MCU (Micro Controller Unit), RGB LED and color sensors. The bookcase as a whole is extendable towards four directions up to nine units with the lighting bookcase at the center. The extended, multiple lighting bookcases are wired to receive power from the main bookcase, and are equipped with RGB LEDs but not with MCUs or color sensors. Receiving power and color signals from the main lighting bookcase, the sub-bookcases feature changing shades of color. Also, it includes IoT(internet of Things). This study is a proposal of a design product, modularized to control the shades of the bookcase lighting using these sensors.

• Applied Microscopy
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• v.24 no.1
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• pp.11-27
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• 1994

The morphological development of the carotid body was studied by electron microscope in human fetuses from 40mm to 260mm crown rump length (10-30 weeks of gestational age). At 40mm fetus, the carotid body was composed of cluster of primitive glomus cells, primitive supporting cells, unmyelinated nerve fibers, and blood capillaries. In connective tissue between internal and external carotid arteries adjacent to the superior cervical sympathetic ganglion, two types of glomus cells through all prenatal period were found. Dark cells contained a dense cytoplasm with conspicuous large dense-cored granules, whereas light cells had a less dense cytoplasm with dense-cored granules. The light cells contained dense-cored granules that were smaller and less abundant than those in the dark cells. The primitive supporting cells appeared star-shaped with attenuated cytoplasmic extensions intervening between the adjacent glomus cells. Synaptic contact between the axon terminals and soma of the glomus cells were first observed at 40mm fetus. In 80-100mm fetus, the carotid body contained tightly packed collection of glomus cells and supporting cells which surrounded the abundant thin-walled blood vessels. Intercellular junctions between the glomus cells and adjacent cells were commonly seen. Nerve endings on the glomus cells have the form of small boutons and the other from of large calyces. During the second half of the fetal period, the glomus cells were completely enveloped by supporting cells and nerve terminals. At 260mm, the morphological features of carotid body were similar to those of human adult. The result of this study demonstrates that there are differences between the carotid body and aorticopulmonary bodies, especially with respect to their synaptic complexes, abundant blood capillaries, and two glomus cell types.