• Journal of applied mathematics & informatics
• /
• v.20 no.1_2
• /
• pp.485-489
• /
• 2006

In this paper, we slightly improve the Baby-step Giant-step for certain elliptic curves. This method gives the running time improvement of $200\%$ in precomputation (Baby-step) and requires half as much storage as the original Baby-step Giant-step method.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.8
• /
• pp.87-93
• /
• 2013

A baby-step giant-step algorithm divides n by n blocks that possess $m={\lceil}\sqrt{n}{\rceil}$ elements, and subsequently computes and stores $a^x$ (mod n) for m elements in the 1st block. It then calculates mod n for m blocks and identifies each of them with those in the 1st block of an identical elemental value. This paper firstly proposes a modified baby-step giant-step algorithm that divides ${\lceil}m/2{\rceil}$ blocks with m elements applying $a^{{\phi}(n)/2}{\equiv}1(mod\;n)$ and $a^x(mod\;n){\equiv}a^{{\phi}(n)+x}$ (mod n) principles. This results in a 50% decrease in the process of the giant-step. It then suggests a reverse baby-step giant step algorithm that performs and saves ${\lceil}m/2{\rceil}$ blocks firstly and computes $a^x$ (mod n) for m elements. The proposed algorithm is found to successfully halve the memory and search time of the baby-step giant step algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.23-29
• /
• 2015

The baby-step giant-step algorithm seeks b in a discrete logarithm problem when a,c,p of $a^b{\equiv}c$(mod p) are already given. It does so by dividing p by m block of $m={\lceil}{\sqrt{p}}{\rceil}$ length and letting one giant walk straight toward $a^0$ with constant m strides in search for b. In this paper, I basically reduce $m={\lceil}{\sqrt{p}}{\rceil}$ to p/l, $a^l$ > p and replace a giant with an adult who is designed to walk straight with constant l strides. I also extend the algorithm to allow $2^k$ adults to walk simultaneously. As a consequence, the proposed algorithm quarters the execution time of the basic adult-walk method when applied to $2^k$, (k=2) in the range of $1{\leq}b{\leq}p-1$. In conclusion, the proposed algorithm greatly shorten the step number of baby-step giant-step.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.6
• /
• pp.25-31
• /
• 2014

When the public key e and the composite number n=pq are disclosed but not the private key d in an asymmetric-key RSA, message decryption is carried out by obtaining ${\phi}(n)=(p-1)(q-1)=n+1-(p+q)$ and subsequently computing $d=e^{-1}(mod{\phi}(n))$. The most commonly used decryption algorithm is integer factorization of n/p=q or $a^2{\equiv}b^2$(mod n), a=(p+q)/2, b=(q-p)/2. But many of the RSA numbers remain unfactorable. This paper therefore applies baby-step giant-step discrete logarithm and $2^k$-ary modular exponentiation to directly obtain ${\phi}(n)$. The proposed algorithm performs a reverse baby-step and $2^k$-ary adult-step. As a results, it reduces the execution time of basic adult-step to $1/2^k$ times and the memory $m={\lceil}\sqrt{n}{\rceil}$ to l, $a^l$ > n, hence obtaining ${\phi}(n)$ by executing within l times.

• Clinical and Experimental Reproductive Medicine
• /
• v.47 no.4
• /
• pp.284-292
• /
• 2020

Objective: This study investigated whether adding outer-well medium to inhibit osmotic changes in culture media in a dry-type incubator improved the clinical outcomes of in vitro fertilization-embryo transfer (IVF-ET) cycles. Methods: In culture dishes, the osmotic changes in media (20 µL)-covered oil with or without outer-well medium (humid or dry culture conditions, respectively) were compared after 3 days of incubation in a dry-type incubator. One-step (Origio) and G1/G2 (Vitrolife) media were used. Results: The osmotic changes in the dry culture condition (308 mOsm) were higher than in the humid culture conditions (285-290 mOsm) after 3 days of incubation. In day 3 IVF-ET cycles, although the pregnancy rate did not significantly differ between the dry (46.2%) and humid culture (51.0%) groups, the rates of abortion and ongoing pregnancy were significantly better in the humid culture group (1.5% and 49.5%, respectively) than in the dry culture group (8.3% and 37.8%, respectively, p<0.05). In day 5 IVF-ET cycles, the abortion rate was significantly lower in the humid culture group (2.2%) than in the dry culture group (25.0%, p<0.01), but no statistically significant difference was observed in the rates of clinical and ongoing pregnancy between the dry (50.0% and 25.0%, respectively) and humid culture groups (59.5% and 57.3%, respectively) because of the small number of cycles. Conclusion: Hyperosmotic changes in media occurred in a dry-type incubator by evaporation, although the medium was covered with oil. These osmotic changes were efficiently inhibited by supplementation of outer-well medium, which resulted in improved pregnancy outcomes.

• Journal of Internet of Things and Convergence
• /
• v.7 no.1
• /
• pp.43-54
• /
• 2021

Purpose: The purpose of this study was to construct a protocol for the prevention of suicide in male baby boomers. Methods: In order to construct the protocol, a three-step expert consensus process was carried out. The first step was to compose questions based on various research data. For this purpose, two professors of psychiatric mental health nursing and two advanced practitioner nurse of psychiatric mental health in the composition. The second step was to conduct the first Delphi survey on expert panelists. The survey period was from October 13, 2015 to November 1, 2015. The third stage, the second Delphi investigation was conducted from November 10 to December 4, 2015. Results: As a result of the survey, a total of 7 areas of protocol configuration items were derived. The derived items include the characteristics of male baby boomers, suicidal signs, suicide risk factors, suicide protection factors, suicide measurement tools, related organizations, and mental health promotion programs. Conclusion: This study can be used as a guideline when intervening suicide prevention of male baby boomers in community mental health centers.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.3
• /
• pp.1090-1099
• /
• 2013

The purpose of this study was to examine difference in life satisfaction by social activity type in baby boomers. Sampling 1,115 baby boomers, gender and region were assigned. A questionnaire survey was carried out from August to October in 2011. As a result of research, first, the typology of social activity in baby boomers includes 3 groups. The passive social-participation type is the cluster to which 36.8% of the baby boomers belong. They do not join income activity or civic-group activity at all. A case of doing religious activity or family activity includes a minority. There are primarily lots of women and posteriori baby boomers. Academic background level or household income is lower compared to other clusters. The life satisfaction level is moderate. Second, the active social-participation type is the cluster to which 33.8% of the baby boomers belong. They are positive in all the social activities including income activity. What there are lots of women and posteriori baby boomers is similar to the passive social-participation type. However, the academic background or the averagely monthly household income is the highest compared to other clusters. Even the life satisfaction level is the highest. Third, the economic activity orientation type is the cluster to which 29.4% of the baby boomers belong. They participate in income activity, but don't participate in civic-group activity, educational activity, and social activity such as spending time alone. Distribution of priori-and-posteriori baby boomers, distribution of academic background, or monthly household income is moderate level of other clusters. However, unlike other clusters, there are many men. The life satisfaction level is the lowest. Based on result of this study are suggested ways to improve in life satisfaction by social activity type in baby boomers.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2011.04a
• /
• pp.290-295
• /
• 2011

The purpose of this paper was to study on the attitudes about Reverse-Mortgage among Baby Boomers to offer the basis for revitalization of Reverse-Mortgage. Social survey research using a questionnaire was conducted among the babyboomer's living in Seoul area from September $30^{th}$ to October $14^{th}$. The data from 102 respondents were analyzed using SPSS PASW 18.0. The main findings were as followings 1) although 64% of the respondents prefered to type which could withdraw temporary cash, but main factor that affected the use was a stability in one's old age 2) 72% of respondents thought adequate age for application was over 66. So lowering the qualification of age looked not need for revitalization 3) babyboomer's said that they would use reverse-mortgage if they couldn't get benefit from other pension inspite of getting lower recognition on house inheritance. It was be cause they regarded Reverse-Mortgage as a final step. In conclusion, current qualification and limit for withdraw looks adequate but it need public relations about its merit unlike other pension. And it has to emphasize its stability so that baby boomer can feel easy from holding a mortgage on their house.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.255-262
• /
• 2015

In the absence of a deterministic algorithm for economic load dispatch optimization problem (ELDOP), existing algorithms proposed as solutions are inevitably non-deterministic heuristic algorithms. This paper, therefore, proposes a balance-and-swap algorithm to solve an ELDOP. Firstly, it balances the initial value to ${\Sigma}P_i=P_d$ by subsequently reducing power generation for each adult-step and baby-step and selects the minimum cost-generating method. Subsequently, it selects afresh the minimum cost-generating method after an optimization of the previously selected value with adult-step baby-step swap and giant-step swap methods. Finally, we perform the $P_i{\pm}{\beta}$, (${\beta}=0.1,0.01,0.001,0.0001$) swap. When applied to the 3 most prevalently used economic load dispatch problem data, the proposed algorithm has obtained improved results for two and a result identical to the existing one for the rest. This algorithm thus could be applied to ELDOP for it has proven to consistently yield identical results and to be applicable to all types of data.

• Fashion & Textile Research Journal
• /
• v.19 no.4
• /
• pp.385-399
• /
• 2017

This study will broaden the application of doll costume product with historical characteristics and the image of unlined cheollik in the $17^{th}$ century period of transition during the Joseon Dynasty. Historical design sources were extracted from old documents and precedent studies. Unlined cheollik of Shin Gyeong-yu, meritorious retainer, were selected as main reference-relic because of various fabric, preserved conditions and definite shape. 'Baby doll' was selected as main model because of consumer preferences and awareness. Design sources from unlined cheollik in the early $17^{th}$ century were about a 1:2 ratio of upper and under parts, removable separated doori-somae, knife-shaped collar (outside), projected square collar (inside), long pleats line, side slit, traditional flat fell seam sewing. Trapezoidal side line, round waistline, and thin fabric were applied in designs because of toddler-body of doll model. Three designs were produced in step 1: Cheollik A focusing on the historical remake (traditional type), Cheollik B with belt and side slit (crossover type), and Cheollik C with back- opening (modern type). In step 2, interview with fashion major student was conducted to increase the utility of designs. As a result, modern trend sources (frill, velcro, round armhole line, slope of sleeves, and floral pattern) were reflected in Cheollik B, C. Finally, three doll cheollik and cheollik-styled doll apron sample were produced. Various versions must be suggested in the study of doll costume products with traditional sources that balance historical characteristics and practicality to improve customer satisfaction.