• The Korean Journal of Applied Statistics
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• v.31 no.1
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• pp.77-96
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• 2018

A reverse mortgage provides a pension until the death for the insured or last survivor. Long-term risk management is important to estimate the contractual period of a reverse mortgage. It is also necessary to study prediction methods of mortality rates that appropriately reflect the improvement trend of the mortality rate since the extension of the life expectancy, which is the main cause of aging, can have a serious impact on the pension financial soundness. In this study, the Lee-Carter (LC) model reflects the improvement in mortality rates; in addition, multiple life model are also applied to a reverse mortgage. The mortality prediction method by the traditional LC model has shown a dramatic improvement in the mortality rate; therefore, this study suggests mortality projection based on the projection of the skewness for the mortality that has been applied to appropriately reflect the improvement trend of the mortality rate. This paper calculates monthly payments using future mortality rates based on the projection of the skewness of the mortality. As a result, the mortality rates based on this method less reflect the mortality improvement effect than the mortality rates based on a traditional LC model and a larger pension amount is calculated. In conclusion, this method is useful to forecast future mortality trend results in a significant reduction of longevity risk. It can also be used as a risk management method to pay appropriate monthly payments and prevent insufficient payment due to overpayment by the issuing institution and the guarantee institution of the reverse mortgage.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.266-271
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• 2009

This study was about three genus of Viola: V. rossii, V. japonica, and V. dissecta var. chaerophylloides which can live together under a deciduous forest canopy. The aim of the study was to directly compare reproductive characteristics of the three species under the same environmental condition. By taking a census of the morphologically different flowers, the results indicate that all three species opened chasmogamous flowers before the canopy of forest closed, but continuously opened cleistogamous flowers after the canopy closed. Numbers of seeds in a capsule followed an ascending order from V. rossii to V. japonica. Mass of seeds followed a descending order from V. rossii to V. japonica. Both results had statistical significance. In terms of characteristics of seed production, V. rossii has been adapted more than V. japonica, and V. dissecta var. chaerophylloides under the deciduous forest.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6052-6059
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• 2012

This paper deals with the Harmonics on the power lines in the computer room. The voltage and current at each phase of electric power from UPS to the load must be ensured less than 5% distortion rates according to the regulation terms from KEPC(Korea Electric Power Corporation) and the KSC4310 Uninterruptible Power Supply regulation. However, measurements show that the voltage distortion rate conforms those regulations but the current distortion rate exceeds much the limit. This current distortion is stabilized from 34.98% to 15.22% nearly half by an AC current filter.

• The Korean Journal of Applied Statistics
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• v.9 no.2
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• pp.161-169
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• 1996

In the design of the sampling, it is important to make a decision about the size of the sample to be selected from the population. We often have a problem to get the optical size of the sample to be considered for cost and time expended for selecting sample unit from highly skewed population. In this case, we give a graphical criterion with Take-all Stratum rate to choose a method and also illustrate the efficiency between the Neyman allocation and the cut-off method with real data.

• TTA Journal
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• s.134
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• pp.130-131
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• 2011

공개경쟁이 대세다. 한때는 '공개 오디션의 아류작이 판을 친다.'는 비판적 목소리가 높았지만, 이제 사람들은 그 치열한 승부에 돌입하고, 심사위원들의 평가에 귀 기울이며, 매회 발전하는 참가자들에 감동한다. 왜 지금 대한민국은 공개경쟁에 열광하는 것일까.

• 건강소식
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• v.36 no.8
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• pp.10-11
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• 2012

비정상적인 다이어트야말로 우리 몸을 망가뜨리는 지름길이 아닐 수 없다. 단기간 감량으로 다이어트를 하는 사람이라면 한번쯤 계획해봤을 원 푸드 다이어트 왜 우리 몸에 치명적인 걸까? 그리고 요요 현상은 왜 오는 것일까?

• Venture DIGEST
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• s.104
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• pp.32-33
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• 2007

대부분의 투자전문가들은 분산투자, 장기투자를 해야 성공할 수 있다고 한다. 어느 재테크, 금융강좌를 가더라도 강사들은 목소리 높여 장기투자를 외치고 있다. 그런데 왜 장기투자를 하는 사람들이 적고, 성공의 사례들이 적은 것일까?

• Aerospace Industry
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• v.83
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• pp.46-48
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• 2004

노즈아트란 무엇인가? 왜 노즈아트의 소재로 여체가 주로 등장하는가? 누가 노즈아트를 그리는가? 왜 기수에 그리는가? 2차대전 당시 사용되었던 항공기들의 복원기를 중심으로 노즈아트에 대해 살펴본다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2792-2799
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• 2015

In this paper, we utilize source mel-frequency cepstral coefficients (SMFCCs), skewness, and kurtosis extracted in glottal flow signals to improve speaker recognition performance. Generally, because the high band magnitude response of glottal flow signals is somewhat flat, the SMFCCs are extracted using the response below the predefined cutoff frequency. The extracted SMFCC, skewness, and kurtosis are concatenated with conventional feature parameters. Then, dimensional reduction by the principal component analysis (PCA) and the linear discriminat analysis (LDA) is followed to compare performances with conventional systems under equivalent conditions. The proposed recognition system outperformed the conventional system for large scale speaker recognition experiments. Especially, the performance improvement was more noticeable for small Gaussan mixtures.

• The Korean Journal of Malacology
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• v.1 no.1
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• pp.24-50
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• 1985

Five different populations of Parafossarulus manchouricus (Chongpyung, Chinju and Kunsan, Korea; and Japan and Taiwan), a population of Bitbynia (Gabbia) misella (Gongju, Korea) and two different populations of Bithynta tentaculata (Michigan, U.S.A. and Bodensee, Germany) were compared in regard to eff-laying characteristics, morphology, chromosome cytology, natural infections of parasites and ecology of habitats. A satisfactory culture method was devised for laboratory rearing of the snails. Tropical fish food (Terra SML) and powdered green leaves (Ceralife) were used as the main food sources for the snails. Benthic diatoms such as Navicula and Gomphonema from the periphyton were also essential for satisfactory growth, especially for the baby snails. The aquaria were stabilized with small stones from a local stream. Young P. manchouricus snails grew to adult size in about 54 days after hatching. They laid eggs 150-156 days after hatching. The whole cycle (birth to egg-laying) took approximately 5 months. The three species of bithyniid snails are iteroparous and lay eggs once a year. There were no major morphological differences in the shells of genera or subgenera studied here. They did exhibit the following rather minor differences. The shell of Parafossarulus has spirally raised ridges, and its apex is usually eroded; the other two genera lack these characteristics. The shell of B. (Gabbia) misella is small, nor exceeding 7.5 mm in length, while the shells of the other two species are larger, being more than 10 mm in length. Scanning electron microscopy (SEM) of the protoconch of P. manchouricus reveals nearly smooth sculpture with small, low, spiral wrinkles. This sculpture is quite different from that of the Hydrobiidae, a family to which the bithyniids are frequently assigned. Scanning electron microscopy of the radulae of the three bithyniid species showed that their radular morphologies are very similar, but there are some small differences, which may be species-specific. There were some statistical differences in shell heights between the Korean and the other populations of P. manchouricus, and between this species and the other two bithyniids as well. The shell differences between the several populations of Korean P. manchouricus may be related to environment. Edtails of the chromosome cycle of these bithyniid snails are similar to those reported for other snails. No specific differences were observed in the chromosome cycle between the various species and populations of snails employed in this study. Reporred for the first time in molluscs are two darkly stained "nucleolar organizers" during pachyterne stages of meiosis. Two different chromosome numbers were observed in the three bithyniid species: n=17 in B. tentaculata and P. manchouricus, and n=18 in B. (G.) misella. no sex chromosomes or supernumerary chromosomes were seen. There were no morphological differences in karyotypes of three Korean strains of P. manchouricus. The infection rates of cercariae of Clonorchis sinensis in Chinju and Kunsan strains of P. manchouricus were 0.14% and 1.25%, respectively. However, Clonorchis cercariae were found in Chongpyung strain of P. manchouriceu and Gongju strain of B. (G.) misella. The habitats of P. manchouricus around Jinyang Lake were relatively clean without any heavy pollution of aquatic microorganisms and organic materials during the period of this study. The levels of dissolved oxygen (D.O.) and biochemical oxygen demand (B.O.D.) of the water specimens sampled from the study areas ranged from 6.0 to 9.6 ppm and from 0.4 to 1.6 ppm, respectively. Eight metalic constituents from the water samples were also assayed, and all metalic ions detercted were remarkably low below the legal criteria. However, calcium ion in the water samples from the habitats of P. manchouricus was considerably higher than others.