• Korean Journal of Poultry Science
• /
• v.30 no.2
• /
• pp.95-99
• /
• 2003

A total of 112 male and 1208 female Ross broiler breeders (30-wk-old) were used in this study to investigate whether a male to female (M/F) ratio of broiler breeder chickens may influence fertility and hatchability of hatching eggs. There were three treatments, each consisting of four pens with a size of 3.2 m ${\times}$ 6.4 m. Each pen housed approx. 100 females and 10 males to give the M/F ratio as follows: T1, 1/9; T2, 1/11; and T3, 1/13, respectively. The fertility of broiler breeder eggs ranged between 93 to 94％ at 30 wk of age. At 35 wk of age, breeder eggs from T3 tended to be less fertile (P>0.05) than those from T1 and T2. The low fertility observed in T3 at 35 wk of age further reduced to reach a statistical significance at 46 wk of age (P<0.05) when compared to those of T1 and T2. Hatchability of breeder eggs among treatments tended to follow a similar trend as shown in fertility, keeping hatchability of breeder eggs from T3 low when compared to the groups of T1 and T2. Our results indicated that the M/F ratio influenced fertility and consequently hatchability of breeder eggs. Furthermore, our study suggests that either 1/9 or 1/11 M/F ratio, but not 1/13 M/F ratio, seems suitable to sustain reproductive performance of broiler breeders throughout the laying periods.

• Journal of the Korean Society for Railway
• /
• v.18 no.6
• /
• pp.578-585
• /
• 2015

Track elastic components can be technically and economically efficient when integrated well into track superstructure of a railway network. In such cases, the elastic rail pad is larger than a 800m radius curve provides smooth rail branching and allows for high-speed operation ($V{\geq}160km/h$). High track resistance causes the tamping intervals to stand out because the constantly increasing share of the sleeper pad further extends the increase of the tamping interval and the long grinding period; the engineering and construction of the small curve radius track provides some measures for reducing the solid sounds. Installation of elastic mats under the ballast can have a good effect, particularly in the context of protection against dust during construction or extensive renovation measures when laying new lines. However, such a process requires special attention and proper installation.

• Journal of Science and Technology Studies
• /
• v.19 no.2
• /
• pp.207-249
• /
• 2019

This study aims to show the dynamics behind official historical descriptions, tracking the development of information system for Seoul Olympic Games. Shortly after the decision was made to host the Seoul Olympics, the South Korean government planned to import a computer system used in the previous Olympics. In response, scientists at Electronic Data Processing Center of KAIST put much effort into persuading the authorities to take the initiative in their own development, and they had to prove their capabilities by developing a computer system that worked safely in the National Sports Festival. With the development of the Olympic information system taking shape, various disputes arose among the host ministries, participating organizations and researchers. As a result, the end product resulted in a modularity of four different systems developed by different agencies, rather than a single system. For this reason, no organization claimed ownership or directly inherited the technical performance of the Olympic computer system, although it was praised as a "gold medal outside the arena." Nevertheless, the technology, hardware and manpower accumulated during the development process have since spread to various areas, laying the groundwork for the development of South Korea's information and communication technology.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.3
• /
• pp.537-541
• /
• 2022

As technology advances, various applications linked to the music industry are becoming popular through new media. There have been many changes in the music market. Beyond the existing music market, where music copyright and performance rights were the center of the music business, we are unifying and operating communication channels that connect artists and fans, such as investment products derived from music copyrights. The technology that connects the fandom with additional business digital content has transformed into global platforms such as HYBE Entertainment's and YG Entertainment's Weverse, as well as SM Entertainment's Bubble. In addition, various national support projects to build a 5G MEC (MobileEdge Computing) environment to quickly respond to the rapidly changing 5G industry ecosystem are supporting for the immersive content demonstration, immersive content testing, and technical analysis, we are laying the groundwork to efficiently respond to the ever-expanding metaverse content market. Technology is changing dramatically. Therefore, we would like to study to changes in the music market brought about by technology and suggest strategies for a new era in the music business.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.1
• /
• pp.85-96
• /
• 2024

As users of paid media readers' satisfaction with usage directly affects the promotion and development of paid media in China. Based on relevant research literature on user sustained use behavior, using the Expectation Confirmation Model as the framework, China paid media Caixin is used as a content product to construct a sustained use model for paid media. At the same time, the operational definition and theoretical assumptions of the variables in the model were provided, laying the foundation for subsequent empirical research on the effectiveness of the model.The research results show that paid media's social influence and performance expectations have a positive impact on Caixin App readers' adoption behavior,perceived usefulness and expection confirmation has a positive impact on Caixin App readers' satisfaction . Adoption behavior and satisfaction has a positive effect on continue using intention, what's more,the perceived usefulness also has a positive effect on continue using intention.

• Korean Journal of Poultry Science
• /
• v.33 no.1
• /
• pp.49-55
• /
• 2006

An experiment was conducted to investigate the effects of feeding Bupleurum falcatum L.(BFL) on performance, blood component and hormonal secretion in broiler breeder hens. A total of 800 broiler breeder hens were allotted to four treatments(BFL ; 0, 0.5, 1.0, 2.0%) with four replications for eight weeks. Weight gain was not significantly different between the groups in growing period($20{\sim}24$ weeks), but egg production and egg mass of broiler breeder hens fed BFL were significantly(p<0.05) higher than those of the control groups in laying period($24{\sim}28$ weeks). Dietary BFL did not affect serum triglyceride concentration, whereas serum cholesterol concentration was significantly increased(p<0.05) in 2.0% BFL-fed groups. No statistical differences were found in serum glucose, Ca, P, Mg, total protein, albumin, GGT, AST, ALT and BUN concentrations. However, albumin/globulin ratio was statistically higher in BFL-fed groups compared to the control groups(p<0.05). Serum estrogen concentrations were significantly increased by feeding a diet containing 0.5% BFL, but progesterone were not influenced. Serum IGF-I of BFL groups was greater than that of control groups at 28 weeks(p<0.05). In conclusion, the results suggest that the dietary addition of BFL into broiler breeder diets improved egg production, serum estrogen and IGF-I concentration, and decreased serum cholesterol concentration and albumin/globulin ratio.

• Korean Journal of Poultry Science
• /
• v.38 no.3
• /
• pp.205-211
• /
• 2011

This work was carried out to investigate the effect of the induced molting diet based on wheat bran on the postmolt performance of layers. Two hundred White Leghorn layers (65-old-wk) with over 80% egg production were used for 8 weeks in this work. Treatments were non-molt control (CO), fasting treatment for 10 days (FW), molt treatment with used molting diet for 4 wk (UM), molt treatment with molting diet based on corn-wheat bran for 4 wk (CW), and molt treatment with molting diet based on wheat bran for 4 wk (WM) as 5 treatments (4 replications/treatment and 10 birds/replication). Feed intake decreased at molting treatments at first weeks and increased after the 3rd week compared to control (P<0.05). Body weight (BW) loss were 18.6% of initial BW at first week in FW treatment, and were 11.4, 14.2 and 17.4% in UM, CW and WM treatments at 4th weeks (P<0.05). Egg production decreased at 1 week in molt treatment and stopped at 2 week in FW, whereas, other molting treatments didn't stop laying eggs. The birds started to lay egg at 4 week in FW and recovered at 5 week in other molting treatments. Egg quality (eggshell thickness, eggshell breaking strength, haugh unit) was high in molting treatments compared with control at 8th weeks (P<0.05). Finally, molting diet based on wheat bran affected BW loss and egg quality such as eggshell thickness, eggshell breaking strength and haugh unit.

• Korean Journal of Poultry Science
• /
• v.31 no.4
• /
• pp.283-291
• /
• 2004

Feeding trials were conducted with Euglena strains grown under different media. The effect of supplementation of Euglena on the laying performance, egg quality and fatty acid composition of egg yolk was studied. In experiment I, two hundred eighty 32-wk-old ISA Brown layers were randomly assigned to seven dietary treatments for 4 wks. Each treatment consisted of 4 replications with 10 birds each housed in two birds cages. Control diet was formulated to have $17\%$ CP and 2,750 kcal ME/kg. Euglena gracilis Z. (EG) was added to control diet at the level of 0.25, 0.5, $1.0\%$ and Euglena gracilis Z. bleached and DHA enriched (EGBD; a strain mutated by streptomycin and cultivated in DHA enriched medium) at the level of 0.5, 1.0, $2.0\%$ in the diet. In experiment 2, three hundred 84-wk-old ISA brown layers were randomly assigned to five dietary treatments: T1; Control, T2; T1 + EGBD $0.5\%$, T3; T1 + Euglena gracilis Z. DHA enriched (EGD; cultivated in DHA enriched medium) $0.5\%$, T4; T1 + EGD $1.0\%$, T5; T1 + EGD $2.0\%$. Each treatment had 5 replication of 12 birds each housed in two birds cages. In experiments 1 and 2, Euglena suppplementation did not significantly affect egg production but increased egg weight and feed intake. In experiment 1, EG was more effective in increasing egg yolk color score than EGBD. Egg yolk color of EG $1\%$ treatment showed the highest score. EGBD supplementation increased DHA concentration of egg yolk. EGBD $2\%$ treatment showed the highest DHA and the lowest palmitic and stearic acids concentration in the egg yolk. In experiment 2, EGBD $0.5\%$ treatment showed highest DHA level in egg yolk (P<0.05). It was conducted that EGBD is a single cell protein source rich in DHA, that can be used to produce DHA enriched eggs.

• Korean Journal of Poultry Science
• /
• v.47 no.2
• /
• pp.95-105
• /
• 2020

This study presents the production characteristics and physiological characteristics of five Korean native chicken (KNC) breeds consisting of Hwanggalsaek Jaeraejong (HJ), Korean Rhode Island Red (KR), Korean White Leghorn (KL), Korean Brown Cornish (KC), and Korean Ogye (KO). We investigated their production performances, vitalities, and stress responses. We measured the survival rate, body weight, age at first egg-laying, hen-day egg production, egg weight, amount of telomeric DNA, heterophil-lymphocyte ratio (H/L ratio), and heat shock protein (HSP)-70, HSP-90α and HSP-90β gene expression levels for 493 KNCs. The survival rate was highest in KR, and lowest in KO. Body weights were steadily high in the order of KC, KR, HJ, KO and KL. Average hen-day egg production was highest in KL, and lowest in KC. While the amount of telomeric DNA was highest in KR, and lowest in KC. Furthermore, both the H/L ratio and the HSP-90β gene expression level were highest in KC, and lowest in KR. These results indicated that the KR breed was highly resistant to stress, whereas KC was more susceptible to stress. Taken together, it is considered that with improvements the KC breed would be more suited to be used as a Korean broiler breed while KL would be more appropriately used as a Korean layer breed. In addition, it is considered that the KR breed is appropriate to be used as a maternal chicken breeder based on good production capacity and excellent robustness, while the HJ breed is desirable to be improved as a high-quality Korean meat breed based on its excellent meat quality.

• Korean Journal of Poultry Science
• /
• v.43 no.3
• /
• pp.177-189
• /
• 2016

This study was conducted to verify the relationships between the expression values of stress-related markers and their production performances in 25 strains of Korean domestic chicken breeds. For stress response markers, the amount of telomeric DNA; expression levels of heat shock protein (HSP)-70, $HSP-90{\alpha}$, and $HSP-90{\beta}$; and comet scores were analyzed. Production performances were measured by the survival rate, body weights, days at first egg laying, egg weight and hen housed egg production. The results showed that the production traits and values of stress-related markers showed significant differences between strains. In general, the stress response of pure bred chickens with heavy weights was relatively high, while that of hybrid chickens with light weights was relatively low. The correlation coefficients between telomere contents and body weights showed that there were weak negative relationships. However, the correlations of telomere content with the survival rate and egg production were weakly positive after 20 weeks old. The expression levels of HSP genes and DNA damage rate (comet scores) were positively correlated to body weight, but were negatively correlated to the survival rate and egg production. The results implied that increasing body weight was associated with increasing HSPs expression and the DNA damage rate was associated with decreasing telomere content. In addition, increasing HSPs expression and the DNA damage rate decreased the survival rate and egg production, but the relationships with the telomere content was the reverse. Correlations among the stress-related markers showed that there were significant correlation coefficients between all of the marker values. HSPs expression was negatively correlated to the telomere content, while it was positively correlated to the DNA damage rate. There was a highly negative correlation between the telomere content and DNA damage rate. In conclusion, increasing the HSP values and DNA damage rate can promote telomere reduction, which led to a decrease in disease resistance and robustness of the chicken. Thus, increasing the stress response was verified to adversely affect the laying performance and viability of chickens.