• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.5A
• /
• pp.421-428
• /
• 2009

Inter-cell coordination has been an emerging issue for mitigating inter-cell interference in broadband wireless access networks such as IEEE802.16 and 3GPP LTE (Long Term Evolution). This paper proposes uplink/downlink hybrid inter-cell coordination patterns for a TDD (Time Division Duplex)/MC-CDMA (Multi-Carrier Code Division Multiple Access) system. For the performance analysis, closed forms of inter-cell interferences are derived when uplink and downlink transmissions coexist over a multi-cell environment. In the analysis, we find an optimal ratio of downlink transmit powers of BSs (Base Stations) based on the target outage probability and the performance according to ratios of uplink/downlink transmit powers of MSs (Mobile Stations)/BSs is explored. Our numerical results show that interference mitigation utilizing the characteristics of the uplink and downlink power ratio is very effective in improving system performance in terms of QoS.

• Journal of the Korean Applied Science and Technology
• /
• v.9 no.1
• /
• pp.1-6
• /
• 1992

New five N-acyl-N-methyl taurate and their sodium salts were synthesized by acylating sodium N-methyl taurate in water in the presense of inorganic alkali as a catalyst. Wherein acyl group is a straight-chain radical of 10 to 18 carbon atoms. These compounds were identified by infrared spectroscopy. Surface activities of these sodium N-acyl-N-methyl taurate including surface tension, Ross-Miles foaming powers, foam stabilities, emulsifying powers and detergency were measured respectively. Also critical micelle concentration(cmc) were evaluated. Consequently these anionic surfactants with long chain acyl amine showed good emulsifying power of O/W type and had a good detergence.

• Journal of Korean Ophthalmic Optics Society
• /
• v.13 no.4
• /
• pp.103-107
• /
• 2008

Purpose: This research measured the near addition powers of presbyopia in wearing the near spectacle for the first time. Methods: We evaluated age, sex, working group, spherical power and cylindrical power and measured the power of refractive error performed the both eyes (310 eyes) of 155 subjects subjectively noncycloplegic and power of addition using the cross cylinder method. Results: There were measured the near addition powers in the range of +0.75D ~ +1.75D. In case of the average addition, they were measured with +1.06D in subjects under 43 years of age, +1.08D in 44 to 46 years, +1.23D in 47 to 49 years and +1.46D in over 50 years of age. The average age in subjects was 47.6 years old and 74 male, 81 female, 71 near sighted working group and 83 far sighted working group. Conclusions: Near addition was correlated with age, working group and cylindrical power (P<0.05, P<0.05, P<0.05).

• Journal of the Optical Society of Korea
• /
• v.20 no.2
• /
• pp.283-290
• /
• 2016

This study presents an 8x four-group inner-focus zoom lens with one-moving group for a compact camera by use of a focus tunable lens (FTL). In the initial design stage, we obtained the powers of lens groups by paraxial design based on thin lens theory, and then set up the zoom system composed of four lens modules. Instead of numerically analytic analysis for the zoom locus, we suggest simple analysis for that using lens modules optimized. After replacing four groups with equivalent thick lens modules, the power of the fourth group, which includes a focus tunable lens, is designed to be changed to fix the image plane at all positions. From this design process, we can realize an 8x four-group zoom system having one moving group by employing a focus tunable lens. The final designed zoom lens has focal lengths of 4 mm to 32 mm and apertures of F/3.5 to F/4.5 at wide and tele positions, respectively.

• Journal of Life Science
• /
• v.19 no.12
• /
• pp.1829-1835
• /
• 2009

Hyperventilation (HV) is routinely induced in order to activate brain waves during an electroencephalogram (EEG). The aim of this study was to examine the effects of HV conditions on EEG and suggested basic data for the standardized procedure. Three degrees of HV were induced for 5 minutes with a ventilation volume of 160 ml/min (control group), 240 ml/min, and 300 ml/min in rats. Powers of delta, theta, alpha, and beta waves were examined by a quantitative EEG. The results showed that there was no significant difference in the powers of all EEG waves between the control and 240 ml/min groups. However, a notable change in EEG powers during HV induced by a ventilation volume of 300 ml/min was observed in the frontal cerebral region as follows: power of the delta was increased by 12.8% (p<0.01), powers of the theta, alpha and beta were decreased by 41.3% (p<0.01), 48.6% (p<0.05), and 41.9% (p<0.05), respectively. Therefore, it is concluded that an increase of about 90% of the normal ventilation volume might be adequate for the hyperventilation, and a useful parameter for evaluation of the qualified hyperventilation might be an alteration of the frontal EEG powers.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.2
• /
• pp.172-178
• /
• 2014

This study suggests the minimum critical external forces based on the assessment of anchoring safety to single anchor situation for representative 8 number of ships in E-group anchorage of Ulsan port. Assessment of anchoring safety is compared holding powers of anchor with external forces of wind, wave and current. Holding powers was reflected materials of seabed, equipment numbers regarding anchor and chain weight, also external forces acting on a hull was calculated considering projected wind area and wetted surface area to the full and ballast conditions respectively. The results of anchoring safety assessments to single anchor showed that the minimum criteria of dragging anchor is a little different from ship's type, size and loading conditions. Bulk carrier can be dragged over the 15m/s of winds and Tanker can be dragged over the 13m/s of winds in case of less than 2knots of currents speed.

• Journal of the Korean Mathematical Society
• /
• v.49 no.4
• /
• pp.745-763
• /
• 2012

We use Kazhdan-Lusztig bases of representations of the symmetric group to express Pfaffians with entries $(a_i-a_j)h_{i+j}$. In the case where the parameters $a_i$ are specialized to successive powers of $q$, and the $h_i$ are complete functions, we obtain the $q$-discriminant.

• Korean Journal of Acupuncture
• /
• v.30 no.2
• /
• pp.135-142
• /
• 2013

Objectives : This study aimed to investigate the general effects of low-frequency electrical stimulation of the ankle joint acupuncture points(BL62 and KI6) on the brain waves of elderly women as a pilot study to figure out the possibility of candidate non-invasive and non-chemical stimulation method for the enhancing the brain function. Methods : A randomized, controlled, double-blinded clinical trial was performed in 31 healthy women(mean age, 54.5 years) within a treatment duration of 12 sessions. In the experimental group, low-frequency electrical stimulation was applied using the maximum range of the individual insensible strength(mean current, $0.04{\mu}A$). The control group received sham stimulation. The background electroencephalographic activity was measured before and after the12 sessions. Results : After 12 sessions of stimulation, the relative power of the alpha wave increased(32 of 32 channels: significant difference in 11 channels, p<0.05); the theta(30 of 32 channels: significant difference in 10 channels, p<0.05), beta(31 of 32 channels), and gamma(30 of 32 channels: significant difference in 7 channels, p<0.05) powers were also decreased compared with the sham group. Conclusions : Electrical stimulation on the ankle joint acupuncture points(BL62 and KI6) seemed to stabilize the elderly women brain by inducing the alpha power and reducing beta, theta, and gamma powers. These results provide insight into the action mechanism of the stimulation and can assist the future developement of a non-invasive and non-chemical treatment technique for stressor related cognitive problems.

• Asian Journal of Innovation and Policy
• /
• v.11 no.2
• /
• pp.222-237
• /
• 2022

As the COVID-19 pandemic crisis left developing countries with economic setbacks, it is high time to highlight that innovative technologies lead the digital economy. The big powers including the United States and China are already implementing industrial policies that involve large-scale fiscal expenditures to secure the lives and safety of their people. To prepare for the future up to 2025, this paper reflects opinions of industry-academia-research experts regarding changes in the external environment and industry trends. By reflecting results of focus group interviews and changes in the external environment and industry trends, a new high-level 5X strategy (Digital Transformation, Energy Transformation, Bio Health Transformation, Supply Chain Transformation, and Research Transformation) to solve national tasks required for the existing ten policy demand fields and ten agenda during lower-level policy implementation stages were derived.

• IE interfaces
• /
• v.25 no.2
• /
• pp.276-282
• /
• 2012

Earned value management(EVM) based progress management was designed to systematically manage large or huge projects with budget based criteria. For this reason, existed methods of EVM based progress management have a practical difficulty to apply to small and medium enterprises(SMEs) not possessing enough human resource, time, and cost. In other words, SMEs have performed simultaneously many small-sized projects emphasizing more project delivery than project budget. This study focuses on the area of project management applying to many small-sized projects simultaneously conducted by SMEs. Thus, the method proposed in this study is to manage only the progress of projects after removing cost factor in order to reduce man powers required for allocating the budget of projects to their all activities in detail in the stage of project planning. This study reveals that SMEs are able to manage progress of many projects easily and intuitively using the proposed method.