• The KIPS Transactions:PartC
• /
• v.15C no.5
• /
• pp.419-428
• /
• 2008

IEEE 802.15.4 reserves transmission time to support real-time transport by sending GTS request packets to the PAN coordinator in advance. This paper introduces GTS-FAT technique to reduce the reservation time by giving a higher sending priority to GTS request packets than data packets. Differently from the conventional scheme where these two kinds of packets share a single transmission queue, GTS-FAT scheme allocates two queues with two different contention window sizes like IEEE 802.11e. This paper also proposes an analytical GTS delay model by combining the two legacy models for 802.15.4 and 802.11e to accurately predict the GTS-FAT delay over a given network topology. Our analysis shows that GTS-FAT reduces GTS service delay by up to 50% at the expense of the data delay by only up to 6.1% when GTS request packets four times outnumber data packets.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.44 no.3
• /
• pp.49-56
• /
• 2007

The IEEE 802.15.4 low rate wireless personal area network is a protocol suitable for wireless sensor networks. Thus there has been growing interest in the IEEE 802.15.4 protocol in the home automation networks. This paper proposes a scheduling scheme obtaining optimal parameters regarding the IEEE 802.15.4 frame and subframes in the home automation networks. Guaranteed time slots (GTS) are exploited for the delivery of real-time traffic. Given a set of the requirements for bandwidths and periods assigned to nodes in the network, the beacon interval and the active/inactive subframe duration satisfying the requirements are selected considering the low duty cycle by the proposed scheme. Based on these parameters, analytic results provide the way to efficient use of network resources including energy.

• Journal of Pharmacopuncture
• /
• v.17 no.1
• /
• pp.70-73
• /
• 2014

Objectives: Yamen is the fifteenth acupoint of the Governor Vessel Meridian (GV15). It is anatomically close to the medulla oblongata, so finding the safety depth of the acupoint is very important. However, few studies on the safety depth of GV15 have been done. Methods: This study tried to measure the safety depth of GV15 by using magnetic resonance imaging (MRI) scans and to analyze the factors affecting the safety depth through multiple regression analyses. This study was carried out for patients who had a brain MRI scan while visiting Jeonju Wonkwang Hospital, Korea. The shortest distance between the glabella and the occipital protuberance (DGO), the horizontal distance between the glabella and the back of the head (DGB) and the dangerous depth (DD) were measured from the sagittal views of the MRI images. The DD is the horizontal distance from the skin's surface at GV15 to the spinal dura mater. Results: The model suggested that the safety depth (SD) was significantly associated with gender (${\beta}$ = 0.474, P < 0.0001), DGO (${\beta}$ = 0.272, P = 0.027), and BMI (${\beta}$ = 0.249, P = 0.005) and the combination of three variables can explain the SD, with $R^2$ = 0.571 (Table 3). A longer SD was associated with males and with greater BMI and DGO. Conclusion: This study suggests that gender, BMI and DGO may be important factors when the SD of GV15 is considered clinically through a multiple regression analysis of GV15.

• Journal of the Korean Dietetic Association
• /
• v.22 no.3
• /
• pp.214-224
• /
• 2016

The purpose of this study was to assess the physical activity of preschool children using an accelerometer and investigate differences related to epoch length setting during use of the accelerometer. Subjects of the study were 26 children (12 boys and 14 girls) at the age of 5, enrolled in one preschool located in Gangneung. From 9:00 a.m. to 4:00 p.m. (7 hours period), every child wore a total of four accelerometers (ActiGraph $GT3X^+$, USA), including three attached to the left hip (with epoch length set at 5 seconds, 15 seconds, and 30 seconds). For comparison purposes, a forth was attached to the opposite position, with epoch length set at 5 seconds. Data collected using 15s epoch and 30s epoch (single larger epoch) were compared with those obtained after reintegration of 5s to 15s epoch, 5s to 30s epoch, and 15s to 30s epoch, respectively (smaller epochs reintegrated). According to the results of this study, there were no significant differences in VM between 30s epoch and 5s to 30s epoch reintegrated and in MVPA (moderate-to-vigorous physical activity), between 15s epoch and 5s to 15s epoch reintegrated. From the Bland-Altman plot, reintegration of 15s to 30s epoch in VM and reintegrations of 15s to 30s epoch and 5s to 15s epoch in MVPA can be recommended for assessing physical activity in preschool children. Further research is needed into the reintegration method while using an accelerometer for assessment of energy expenditure in children.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1992.05a
• /
• pp.91-96
• /
• 1992

The nonvolatile SNOSFET EEPROM memory devices with the channel width and iength of 15[$\mu\textrm{m}$]${\times}$15[$\mu\textrm{m}$], 15[$\mu\textrm{m}$]${\times}$1.5[$\mu\textrm{m}$] and 1.9[$\mu\textrm{m}$]${\times}$1.7[$\mu\textrm{m}$] were fabricated by using the actual CMOS 1 [Mbit] process technology. The charateristics of I$\_$D/-V$\_$D/, I$\_$D/-V$\_$G/ were investigated and compared with the channel width and length. From the result of measuring the I$\_$D/-V$\_$D/ charges into the nitride layer by applying the gate voltage, these devices ere found to have a low conductance state with little drain current and a high conductance state with much drain current. It was shown that the devices of 15[$\mu\textrm{m}$]${\times}$15[$\mu\textrm{m}$] represented the long channel characteristics and the devices of 15[$\mu\textrm{m}$]${\times}$1.5[$\mu\textrm{m}$] and 1.9[$\mu\textrm{m}$]${\times}$1.7[$\mu\textrm{m}$] represented the short channel characteristics. In the characteristics of I$\_$D/-V$\_$D/, the critical threshold voltages of the devices were V$\_$w/ = +34[V] at t$\_$w/ = 50[sec] in the low conductance state, and the memory window sizes wee 6.3[V], 7.4[V] and 3.4[V] at the channel width and length of 15[$\mu\textrm{m}$]${\times}$15[$\mu\textrm{m}$], 15[$\mu\textrm{m}$]${\times}$1.5[$\mu\textrm{m}$], 1.9[$\mu\textrm{m}$]${\times}$1.7[$\mu\textrm{m}$], respectively. The positive logic conductive characteristics are suitable to the logic circuit designing.

• Clinical and Experimental Pediatrics
• /
• v.55 no.12
• /
• pp.487-490
• /
• 2012

We report a case of isodicentric chromosome 15 (idic(15) chromosome), the presence of which resulted in uncontrolled seizures, including epileptic spasms, tonic seizures, and global developmental delay. A 10-month-old female infant was referred to our pediatric neurology clinic because of uncontrolled seizures and global developmental delay. She had generalized tonic-clonic seizures since 7 months of age. At referral, she could not control her head and presented with generalized hypotonia. Her brain magnetic resonance imaging scans and metabolic evaluation results were normal. Routine karyotyping indicated the presence of a supernumerary marker chromosome of unknown origin (47, XX +mar). An array-comparative genomic hybridization (CGH) analysis revealed amplification from 15q11.1 to 15q13.1. Subsequent fluorescence in situ hybridization analysis confirmed a idic(15) chromosome. Array-CGH analysis has the advantage in determining the unknown origin of a supernumerary marker chromosome, and could be a useful method for the genetic diagnosis of epilepsy syndromes associated with various chromosomal aberrations.

• Nutrition Research and Practice
• /
• v.2 no.2
• /
• pp.134-137
• /
• 2008

Atherosclerosis is characterized by a chronic inflammatory disease, and chemokines play an important role in both initiation and progression of atherosclerosis development. Leukotactin-1 (Lkn-1/CCLl5), a new member of the human CC chemokine family, is a potent chemoattractant for leukocytes. Our previous study has demonstrated that Lkn-1/CCL15 plays a role in the initiation of atherosclerosis, however, little is currently known whether Lkn-1/CCL15 is associated with the progression of atherosclerosis. Matrix metalloproteinases (MMPs) in human coronary atherosclerotic lesions playa crucial role in the progression of atherosclerosis by altering the vulnerability of plaque rupture. In the present study, we examined whether Lkn-1/CCLl5 modulates MMP-9 release, which is a prevalent form expressed by activated macrophages and foam cells. Human THP-1 monocytic cells and/or human peripheral blood monocytes (PBMC) were treated with phorbol myristate acetate to induce their differentiation into macrophages. Foam cells were prepared by the treatment of THP-1 macrophages with human oxidized LDL. The macrophages and foam cells were treated with Lkn-1/CCL15, and the levels of MMP-9 release were measured by Gelatin Zymography. Lkn-1/CCL15 significantly enhanced the levels of MMP-9 protein secretion from THP-1 monocytic cells-derived macrophages, human PBMC-derived macrophages, as well as macrophage-derived foam cell in a dose dependent manner. Our data suggest that the action of Lkn-1/CCL15 on macrophages and foam cells to release MMP-9 may contribute to plaque destabilization in the progression of atherosclerosis.

• Journal of Korea Society of Industrial Information Systems
• /
• v.15 no.5
• /
• pp.19-27
• /
• 2010

In this paper, we propose a scheme for real-time data retransmission in LR-WPAN to support the required QoS even in the severe channel error environments. In IEEE 802.15.4a, as the user data rate is supported up to 850Kbps, the real-time streaming data can be transferred more easily. In this research, we study the beacon-enabled mode in IEEE 802.15.4 LR-WPAN standard. In the proposed scheme, special slots are dynamical1y assigned for retransmission of the packet that fails during a real-time data service, and in the severe channel error environments a time diversity is acquired. Analytical results show that the proposed scheme is more robust and achieves a much higher throughput than the previous protocol in LR-WPAN.

• Journal of Species Research
• /
• v.7 no.2
• /
• pp.151-160
• /
• 2018

Seven bacterial strains, 15J4M-1, 15J13-8, 16MFM10, 15J1-8, SR1-5-4, 15J13-6, and 15J8-11 assigned to the phylum Actinobacteria, Bacteroidetes, and Firmicutes were isolated from soil samples collected from Jeju, Korea. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strains 15J4M-1, 15J13-8, 16MFM10, 15J1-8, SR1-5-4, 15J13-6, and 15J8-11 were most closely related to Bacillus selenatarsenatis $SF-1^T$ (with 99.4% similarity), Brevibacterium luteolum $CF87^T$ (99.5%), Carnobacterium iners CCUG $62000^T$ (99.6%), Exiguobacterium profundum $10C^T$ (99.3%), Larkinella insperata LMG $22510^T$ (99.3%), Pseudokineococcus lusitanus CECT $7306^T$ (99.4%), and Spirosoma endophyticum $EX36^T$ (99.3%), respectively. This is the first report of these seven species in Korea.

• Korean Chemical Engineering Research
• /
• v.48 no.6
• /
• pp.763-767
• /
• 2010

High-pressure phase behavior for the binary mixture of 1-propanol with supercritical $CO_2$ has been measured by means of a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The equilibrium loci of the pressure - composition and pressure - temperature were obtained for the binary mixture of 1-propanol + $CO_2$ system at 305.15 K, 313.15 K, 323.15 K and 333.15 K, and from 2 MPa to 11 MPa. The critical temperature of the mixture increased with the temperature. The pressure-composition line for the binary mixture of $CO_2$-1-propanol system showed a typical type-II phase behavior. The experimental P-x envelopes were correlated by using the Peng-Robinson equation of state in a satisfactory manner to obtain the parameters with $k_{ij}=0.116$ and ${\eta}_{ij}=-0.065$.