• Title/Summary/Keyword: Critical period

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An Improvement of Implementation Method for Multi-Layer AHB BusMatrix (ML-AHB 버스 매트릭스 구현 방법의 개선)

  • Hwang Soo-Yun;Jhang Kyoung-Sun
    • Journal of KIISE:Computer Systems and Theory
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    • v.32 no.11_12
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    • pp.629-638
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    • 2005
  • In the System on a Chip design, the on chip bus is one of the critical factors that decides the overall system performance. Especially, in the case or reusing the IPs such as processors, DSPs and multimedia IPs that requires higher bandwidth, the bandwidth problems of on chip bus are getting more serious. Recently ARM proposes the Multi-Layer AHB BusMatrix that is a highly efficient on chip bus to solve the bandwidth problems. The Multi-Layer AHB BusMatrix allows parallel access paths between multiple masters and slaves in a system. This is achieved by using a more complex interconnection matrix and gives the benefit of increased overall bus bandwidth, and a more flexible system architecture. However, there is one clock cycle delay for each master in existing Multi-Layer AHB BusMatrix whenever the master starts new transactions or changes the slave layers because of the Input Stage and arbitration logic realized with Moore type. In this paper, we improved the existing Multi-Layer AHB BusMatrix architecture to solve the one clock cycle delay problems and to reduce the area overhead of the Input Stage. With the elimination of the Input Stage and some restrictions on the arbitration scheme, we tan take away the one clock cycle delay and reduce the area overhead. Experimental results show that the end time of total bus transaction and the average latency time of improved Multi-Layer AHB BusMatrix are improved by $20\%\;and\;24\%$ respectively. in ease of executing a number of transactions by 4-beat incrementing burst type. Besides the total area and the clock period are reduced by $22\%\;and\;29\%$ respectively, compared with existing Multi-layer AHB BusMatrix.

A Study on the Current status and the Educational Needs of Entrepreneurship Education Program : Focused on Elementary and Secondary School Teachers (초·중등 기업가정신 교육 현황과 교육요구도 분석: 초·중등 교사를 대상으로)

  • Baek, Min-Jung;Kang, Kyoung-Kuen;Yi, Bum Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.564-574
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    • 2017
  • This study reviews the current status of entrepreneurship education programs in elementary and secondary schools, and analyzes the following educational needs among teachers. We have made the following conclusions from the study. First, career development teachers shared a strong need for entrepreneurship education programs. Second, the programs provided by these teachers were substandard despite the strong need expressed. In particular, insufficient training period and incentives were provided to teachers involved in the programs, and the teachers exhibited low standards in job specialization and class evaluation abilities. Third, the awareness of people involved in the education scheme was most critical in the cultivation and activation of entrepreneurship educations-according to the Borich educational demand calculations comparing the required and actual entrepreneurship education standards. In summary, the general educational conditions, such as the teachers' job specialization, educational support and environment, and partakers' awareness, were lacking in entrepreneurship education programs aimed at the youth. To stimulate the programs' effectiveness, teachers must be better trained; the programs should be better advertised; and specialization should be cultivated during training. Furthermore, the government's support towards program development and diversification through appropriate policies should aim to help the education's recipients in their proactive career development during the current 4th industrial revolution.

A Study on the shelf-life of IR screening smoke launcher grenade (적외선 차장 연막유탄 신뢰도 및 저장수명 연구)

  • Lee, Jongchan;Lee, Junhyuk;Jung, Hyunsuk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.4
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    • pp.437-445
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    • 2020
  • Smoke grenades are the primary means of protection used by tanks to disrupt enemy detection systems. Such smoke grenades are a critical factor that determines the survival of tanks in the engagement of ground weapon systems, but it can only be used once. Owing to its destructive property, the performance and safety of the smoke grenade cannot be confirmed prior to use. Therefore, the reliability of smoke grenades can be evaluated through various tests during the storage period. This paper presents the results of estimating the reliability and shelf life of IR screening smoke grenade launchers based on the result of the Ammunition Stockpile Reliability Program conducted in 2019. Among the smoke grenade launcher lots currently stored, 16 lots and samples were selected for each year of manufacture and tested. The reliability and shelf life were estimated by examining the number of defects and the change in quality characteristics of each test item. The results of this study can be used to assess the reliability of the smoke grenade launchers and to improve the quality of manufacturing sites.

Study on Relationship between the Obesity Index and the Refractive Power in Adolescent (청소년기 비만도 지수와 굴절력과의 상관성 연구)

  • Lee, Wan-Seok;Ye, Ki-Hun;Shin, Bum-Joo
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.3
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    • pp.329-339
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    • 2013
  • Purpose: In this study, nutrient intake during the adolescent period is a critical time for the development of the vision. Therefore we analyzed the relationship between the obesity index and the refractive power. Methods: We used the Korean National Health and Nutrition Examination Survey 2010 document. The obesity index is classified as Broca index (less than 80.0% is low weight, 80 to 89.9% is underweight, 90.0 to 109.9% is normal, overweight is from 110.0 to 119.9%, 120.0% or more is obesity) and body mass index (BMI)(less than 18.5 is underweight, 18.6~22.9 is normal, 23.0 to 24.9 is overweight, and obesity is higher than 25.0). We analyzed correlation with the body mass index and refractive error in adolescent. Results: As shown in the statistics, according to Broca index and body mass index (BMI), the refractive power and the obesity index showed a statistically significant correlation in the ages 15 to 18. Under weight subjects are ingested 43.84% dietary fiber, vitamin C 56.55%, 35.20% iron, 31.84% of, and 38.03% potassium less than the average food intake by the standard group. Conclusions: Moderate weight with a broad variety of taking nutrition and good eating habits seems to have an effect to the good growth and the good vision.

Evaluation of Domestic CCPs(Coal Combustion Products) Quality by API Test Method (API시험법에 의한 국내 석탄회의 품질 평가)

  • Yoo, Sung-Won;Yu, Kyung-Geun;Cho, Young-Keun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.1 no.1
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    • pp.49-57
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    • 2013
  • Recently, recycling of industrial by-products and CO2 reduction have been important issues in the world. In this reason, applications and reuse of Fly ash as a binder for concrete, which is generated in thermoelectric power plant, have been one of the effective recycle methods. In order for Fly ash to be applied to concrete, Korean Standard(KS) has selected and managed quality such as $SiO_2$, fineness, specific gravity, ignition loss and activity index. However, there is a limits for activity index, whose test period required is at least 28 days or 91 days. Activity index is the critical indication standard to determine mechanical strength of concrete that contained Fly ash. To complement the disadvantage of test method, this research provided "API test method", which quickly measure Pozzolanic reaction of Fly ash can be considered as a alternative of activity index. Then, the adaptable API test method need to be investigated through comparative analysis with the test result of API, activity index and K-value. The test method can make evaluation of Fly ash quality faster and more accurate. As a result, most Fly ash produced in Korea has not been satisfied in the KS quality standard except water content and specific gravity, and especially fluidized bed boiler ash has its characteristics. Also, API, activity index and K-value have superior interrelationship. The interrelationship between API and activity index and K-value gets increased as the material age gets higher, so API test can be considered as very useful test method for Pozzolanic reaction evaluation of Fly ash.

Chemical Neurolytic Block with Absolute Ethyl Alcohol on Cervical Sympathetic Ganglion in Rabbits (토끼에서 경부 교감신경절의 무수 에틸 알코올에 의한 화학적 차단)

  • Kang, Yoo-Jin;Suh, Jae-Hyun
    • The Korean Journal of Pain
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    • v.7 no.2
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    • pp.162-169
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    • 1994
  • Blockade of cervicothoracic sympathetic ganglion (stellate ganglion controls pain on face, head, neck, shoulder, upper limbs, and upper chest, including their viscera and sympathetically maintained pain. This procedure also increases blood flow to the above areas and relieves hyperreactivity of sympathetic nervous system. Clinically, repeated stellate ganglion blocks with local anesthetic agent may become difficult with complications such as accidental intravascular or subdural injection, recurrent laryngeal nerve or bracheal plexus paralysis, pneumothorax and edema on injection site. Therefore, at times long-term cervicothoracic ganglion block with neurolytics is necessitated but its applications are prohibited by the critical structures surrounding ganglion. There are also few reports of neurolytic stellate ganglion block. This study was performed to observe the complications, gross changes of surrounding structures, and microscopic findings of ganglion cells after neurolytic block and to certify the possibility of clinical use of neruolytic stellate ganglion block. The unilateral superior cervical sympathetic ganglion of rabbit was blocked with absolute ethyl alcohol 0.4 ml at the level of cricoid cartilage. Normal ganglion was used as a control and 5 animals were sacrificed at each intervals of 7, 15 and 50 days after block. The results were as follows; 1) All experimental animals showed no specific changes of behavior, motor function. No necrotic tissues were present in the block area during the observation period. There were some gross scar tissues along the fascia of muscles surrounding the needle injection site, but gross atrophy of muscles or injured major vessels were not found. 2) Microscopically, structures of normal ganglion of rabbit were very similar to those of humans. Seven days after absolute ethyl achohol injection there were marked edema of ganglion cells and nuclei with irregular nuclear membrane. Some of the ganglion cells lost their nuclei and showed degenerative changes. Fifteen days after block, cell edema were decreased and loss of the Nissl's body was prominant. The ganglion cell structures looked close to normal but the cytoplasm and nucleus were generally contracted 50 days after block. These results suggest absolute ethyl alcohol injection on cervical sympathetic ganglion with above method mainly blocks pre- and post-synaptic fibers and the long-term neurolytic blockade of this ganglion may be possible in rabbits.

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A Study on the Role of Public Fund for Improvement of Korean Animation Funding System (한국 애니메이션 재원조달 활성화 방안 연구 : 공적기금의 역할을 중심으로)

  • Kim, Young-Jae
    • Cartoon and Animation Studies
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    • s.18
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    • pp.17-35
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    • 2010
  • The purpose of this study is to find out the way to improve the funding system of Korean animation, which will lead the establishment of virtuous circle of Korean animation industry. The funding structure of Korean animations in the period of 2005-2009 is analyzed to find out that the funding surveyed to find out that the domestic funding source for Korean animation has reached its limitation. Without any active involvement of public fund, this will result in the shrink of Korean animation industry with heavy reliance on foreign capital and limited quality of Korean animation. This is not only a serious problem of Korean animation industry, but also the problem of Korean cultural identity and variety because it is related with the diminish and degradation of Korean children and family content. Meanwhile, in France and Canada, which are the major co-production partners of Korean animation, the animation production is being activated by the full support of government fund system, because the animation is regarded as the important genre which plays a critical public role in establishing the cultural identity and variety of such countries. Improvement of Korean animation funding system is not pursued by more injection of public fund into the industry. It should be designed to facilitate the investment from the private sector by improving the profitability of Korean animation. This goal can be achieved by public fund with annual budget of 25 billion Korean Won supporting the distribution and production of Korean animation. Discussion should be needed for securing the funding resources such as establishment of new animation fund or utilization of existing fund.

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Neuroendocrine Control of Gonadotropin Secretion during the Menstrual Cycle

  • Ryu, Kyung-Za
    • The Korean Journal of Pharmacology
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    • v.23 no.2
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    • pp.57-75
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    • 1987
  • Two modalities of gonadotropin secretion, pulsatile gonadotropin and preovulatory gonadotropin surge, have been identified in the mammals. Pulsatile gonadotropin secretion is modulated by the pulsatile pattern of GnRH release and complex ovarian steroid feedback actions. The neural mechansim that regulates the pulsatile release of GnRH in the hypothalamus is called "GnRH pulse generator". Ovarian steroids, estradiol and progesterone, appear to exert thier feedback effects both directly on the pituitary to modulate gonadotropin release and on a hypothalamic site to modulate GnRH release; estradiol primarily affects the amplitude while progesterone decreases the frequency of the pulsatile GnRH. Steroid hormones are known to affect catecholamine transmission in brain. MBH-POA is richly innervated by NE systems and close apposition of NE terminals and GnRH cell bodies occurs in the MBH as well as in the POA. NE normally facilitates pulsatile LH release by acting through ${\alpha}-receptor$ mechanism. However, precise nature of facilitative role of NE transmission in maintaining pulsatile LH has not been clearly understood. Close apposition of DA and GnRH terminals in ME might permit DA to influence GnRH release. Action of DA transmission probably is mediated by axo-axonic contacts between GnRH and DA fibers in the ME. Dopamine transmission does not normally regulate pulsatile LH release, but under certain conditions, increased DA transmission inhibit LH pulse. Endogenous opioid acts to suppress the secretion of GnRH into hypophysial portal circulation, thereby inhibiting gonadotropin secretion. However, an interaction between endogenenous opioid peptides and gonadotropin release is a complex one which involves ovarian hormones as well. LH secretion appears to be most suppressed by endogenenous opioids during the luteal phase, at a time of elevated progesterone secretion. The arcuate nucleus contains not only cell bodies for GnRH and ${\beta}-endorphin$ but also a dense aborization of fibers suggesting that GnRH release is changed by the interactions between GnRH and ${\beta}-endorphin$ cell bodies within the arcuate nucleus. The frequency and amplitude of pulsatile LH release seem to be increased during the preovulatory gonadotropin surge. Estradiol exerts positive feedback action on the hypothalamo-pituitary axis to trigger preovulatory LH surge. GnRH is also crucial hormonal stimulus for preovulatory LH surge. It is unlikely, however, that increased secretion of GnRH during the preovulatory gonadotropin surge represents an obligatory neural signal for generation of the LH discharge in primates including human. Modulation of preovulatory LH surge by catecholamines has been studied almost exclusively in rats. NE and E may be involved in distinct way to accumulate GnRH in the MBH and its release into the hypophysial portal system during the critical period for LH surge on proestrus in rats. However, the mechanisms whereby augmented adrenergic transmission may facilitate the formation and accumulation of GnRH in the ME-ARC nerve terminals before the LH surge have not been clearly understood.

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Selection of Optimal Vegetation Indices for Estimation of Barley & Wheat Growth based on Remote Sensing - An Application of Unmanned Aerial Vehicle and Field Investigation Data - (원격탐사 기반 맥류 작황 추정을 위한 최적 식생지수 선정 - UAV와 현장 측정자료를 활용하여 -)

  • Na, Sang-il;Park, Chan-won;Cheong, Young-kuen;Kang, Chon-sik;Choi, In-bae;Lee, Kyung-do
    • Korean Journal of Remote Sensing
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    • v.32 no.5
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    • pp.483-497
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    • 2016
  • Unmanned Aerial Vehicle (UAV) imagery are being assessed for analyzing within field spatial variability for agricultural precision management, because UAV imagery may be acquired quickly during critical periods of rapid crop growth. This study refers to the derivation of barley and wheat growth prediction equation by using UAV derived vegetation index. UAV imagery was taken on the test plots six times from late February to late June during the barley and wheat growing season. The field spectral reflectance during growing period for the 5 variety (Keunal-bori, Huinchalssal-bori, Saechalssal-bori, Keumkang and Jopum) were measured using ground spectroradiometer and three growth parameters, including plant height, shoot dry weight and number of tiller were investigated for each ground survey. Among the 6 Vegetation Indices (VI), the RVI, NDVI, NGRDI and GLI between measured and image derived showed high relationship with the coefficient of determination respectively. Using the field investigation data, the vegetation indices regression curves were derived, and the growth parameters were tried to compare with the VIs value.

Azimuthal Distribution of Daily Maximum Temperatures Observed at Sideslopes of a Grass-covered Inactive Parasitic Volcano ("Ohreum") in Jeju Island (제주도 초지피복 기생화산("오름")의 방위별 일 최고기온 분포)

  • Seo, Hee-Chul;Jeon, Seung-Jong;Yun, Jin-I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.10 no.1
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    • pp.25-31
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    • 2008
  • Information on daily maximum air temperature is important in predicting the status of plants and insects, but the uneven and sparse distribution of weather stations prohibits timely access to the data in regions with complex topography. Since cumulative solar irradiance plays a critical role in determining daily maximum temperature on any sloping surfaces, derivation of a quantitative relationship between cumulative solar irradiance and the resultant daily maximum temperature is a prerequisite to development of such estimation models. Air temperatures at 8 sideslope locations with similar elevation and slope angle but aspect, circumventing a cone-shaped, grass-covered parasitic volcano (c.a., 570 m diameter for the bottom circle and 90m bottom-to-top height), were measured from June to December in 2007. Daily maximum temperatures from each location were compared with the average of 8 locations (assumed to be the temperature measured at a "horizontal reference" position). The temperature deviation at all locations increased with the day of year (or sun elevation) from summer solstice to winter solstice. Averaged over the entire period, the south facing location was warmer by $1^{\circ}C$ in daily maximum temperature than "horizontal reference" and the north facing location was cooler by $0.8^{\circ}C$ than the reference, resulting in the year round average south-north temperature difference of $1.8^{\circ}C$. In November, both south and north facing slopes showed the greatest deviation of $+2.0^{\circ}C$ and $-1.3^{\circ}C$, respectively in daily maximum temperature at monthly scale. On a daily scale, the greatest deviation was +3.8 and $2.7^{\circ}C$ at the south and north slope, respectively. The cumulative solar irradiance (on the slope for 4 hours from 11:00 to 15:00 TST) explained >60% of the variance in daily maximum temperature deviations among 8 locations, suggesting a feasibility of developing an estimation model for daily maximum temperature over complex topography at landscape scales.