• Journal of Technology Innovation
• /
• v.29 no.3
• /
• pp.1-31
• /
• 2021

With the growing importance of technology innovation as a key factor for firms' competitive advantage, 'innovation persistence' became also an important research subject. 'Innovation Persistence' is a concept that indicates whether or not firms' innovation activity or performance continues. However, the data used for innovation studies are carried out as cross-sectional surveys in most countries. For this reason, studies dealing with longitudinal aspect of innovation persistence are rare. In particular, there is almost no research on innovation persistence using Korean innovation survey data. This study reviews the concepts and characteristics of innovation persistence based on extant literature, and perform an empirical analysis on the status and features of Korean firms' technology innovation persistence. Based on the data of the Korean Innovation Survey (KIS) conducted every other year from 2012 to 2018, panel data on 3,379 firms which observed multiple times are constructed. As a result, only part of the firms with persistent innovation were observed (for innovation performance 10~12%, for innovation activity 15~17%), and it was found that the persistence of non-innovation was remarkable(about 52~57%). And it was confirmed that the persistence of innovation activities is stronger than that of innovation performance. Besides, some features by sub-types of innovation appeared. Product innovation showed higher persistence than process innovation, and internal R&D also showed higher persistence than joint/external R&D. As a result of additional logit analysis to identify factors, it was found that radical or gradual product innovation is the most influential factor in persisting innovation in the next period. Since the sample selection bias due to a limitations of raw data might exist in the panel data constructed in this study, it should be noted that faulty generalization of the results are not allowed. Nevertheless, this is the first study to examine the technology innovation persistence targeting Korean firms and is expected to be a starting point for follow-up studies. It is anticipated that advanced research results will be drawn through the establishment of official panel data and improved methodologies.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.6
• /
• pp.245-253
• /
• 2021

RC slab bridges account for the largest portion of deteriorated bridges in Korea. However, most RC slabs are not included in the first and second classes of bridges, which are subject to bridge safety management and maintenance. The highest damaged components in highway bridges are the subsidiary facilities including expansion joints and bearings. In particular, leakage through expansion joints causes deterioration and cracks of concrete and exposure of reinforced bars. Therefore, this study analyzed the effect of adhesion damage at expansion joints on the response of the deck in RC slab bridges. When the spacing between the expansion joints at both ends was closely adhered, cracks occurred in the concrete at both ends of the deck due to the resistance rigidity at the expansion joints. Based on the response results, the correlation analysis between displacements in the longitudinal direction of the expansion joint and concrete stress at both ends of the deck for each damage scenario was performed to investigate the effect of the occurrence of damage on the bridge behavior. When expansion joint devices at both sides were damaged, the correlation between displacement and stress showed a low correlation of 0.18 when the vehicles proceeded along all the lanes. Compared with those in the intact state, the deflections of the deck in the damaged case at both sides showed a low correlation of 0.34 to 0.53 while the vehicle passed and 0.17 to 0.43 after the vehicle passed. This means that the occurrence of cracks in the ends of concrete changed the behavior of the deck. Therefore, data-deriven damage detection could be developed to manage the damage to expansion joints that cause damage and deterioration of the deck.

• Ecology and Resilient Infrastructure
• /
• v.8 no.4
• /
• pp.223-232
• /
• 2021

In general, stormwater flows to the road surface, especially in urban areas, and it is discharged through the drainage grate inlets on roads. The appropriate evaluation of the road drainage capacity is essential not only in the design of roads and inlets but also in the design of sewer systems. However, the method of road surface flow analysis that reflects the topographical and hydraulic conditions might not be fully developed. Therefore, the enhanced method of road surface flow analysis should be presented by investigating the existing analysis method such as the flow analysis module (uniform; varied) and the flow travel time (critical; fixed). In this study, the algorithm based on varied and uniform flow analysis was developed to analyze the flow pattern of road surface. The numerical analysis applied the uniform and varied flow analysis module and travel time as parameters were conducted to estimate the characteristics of rainfall-runoff in various road conditions using the developed algorithm. The width of the road (two-lane (6 m)) and the slope of the road (longitudinal slope of road 1 - 10%, transverse slope of road 2%, and transverse slope of gutter 2 - 10%) was considered. In addition, the flow of the road surface is collected from the gutter along the road slope and drained through the gutter in the downstream part, and the width of the gutter was selected to be 0.5 m. The simulation results were revealed that the runoff characteristics were affected by the road slope conditions, and it was found that the varied flow analysis module adequately reflected the gutter flow which is changed along the downstream caused by collecting of road surface flow at the gutter. The varied flow analysis module simulated 11.80% longer flow travel time on average (max. 23.66%) and 4.73% larger total road surface discharge on average (max. 9.50%) than the uniform flow analysis module. In order to accurately estimate the amount of runoff from the road, it was appropriate to perform flow analysis by applying the critical duration and the varied flow analysis module. The developed algorithm was expected to be able to be used in the design of road drainage because it was accurately simulated the runoff characteristics on the road surface.

• 한국노년학
• /
• v.38 no.3
• /
• pp.705-723
• /
• 2018

In this study we review the selected articles on elderly health and medical care published in the Journal of the Korea Gerontological Society (JKGS) in the last 40 years, and make suggestions for future research directions for gerontological health and medical care issues. Of all the 40 year publications from volume 1 (1980) to 38 (2017), we first examined the 30th anniversary review on the subject of gerontological nursing care and healthcare policies published in JKGS from 1980 (vol. 1, No. 1) to 2008 (vol. 28, No. 2), and reviewed recent 237 researches of this decade (out of all 655 articles from 2008, vol. 28, No. 3 to 2017, vol. 38, No. 4). We could find the following trends. Firstly, the analysis of the primary authors in the past 10 years revealed that those in public health, nursing and other health-related including physical education areas have dealt the subjects focusing on physical health while those in social welfare mostly on mental health. That is, physical health has been the prime subject of researches in the health and medical care area. Secondly, in the same period quantitative researches were accounted for 89.9%, which is similar to the trend of the first 30 years 81.5 %. On the other hand, qualitative studies were only 11 cases and the focus group interview were the most frequently used method comprising 33.3% among them. Thirdly, the non-experimental researches in the past 10 years comprise 65.4%, which was 82.7% in 1980 2008 period, indicating the increasing trend in experimental researches to deal with the issues in medical and healthcare fields. Lastly, the subjects of the researches were mostly the elders who are healthy, residents of city areas, or home dwellers, and 60% of them were over 65 years old in the past 10 years while the proportion was 42.7% in the previous review period. 81.6 % of the researches in the past 10 years was dealing both genders, slightly decreased trend compared to 88.5% of the previous review period. This study reveals that the researches in non-experimental physical health remains the main stream of JKGS despite the efforts by some researchers to diversify the methods and subjects. Systematic and in-depth researches employing multidisciplinary, qualitative, longitudinal and meta-analytical approaches are called for to guide the gerontolgical health issues with preventive and proactive perspectives.

• 한국노년학
• /
• v.38 no.3
• /
• pp.551-567
• /
• 2018

Demographic and socio-structural information is useful to identify potential welfare recipients who are in need of disease-prevention and intervention services. Thus, the present study aims to explore the differences in grip strength among middle and old-aged adults by living conditions and by living area. The 5th wave data of Korean Longitudinal Study of Aging was utilized. The dependent variable was grip strength, and the independent variables were living alone (living alone or not) and living area (city or non-city). Covariates were age, education, log-transformed household income, spouse existence, body mass index, self-rated health conditions, depressive symptoms, cognitive function, smoking, regular exercise, frequency of meeting with friends, and the number of social participation. Regression analysis was performed for middle-aged men, middle-aged women, old-aged men, and old-aged women, respectively. ANOVA and Chi-test were additionally used to specifically discuss significant results. Cross-sectional weight was applied to all analyses. According to the results, living alone and living area did not have significant effects on grip strength among middle-aged men, old-aged men, and old-aged women. In middle-aged women, however, living alone and living area were significantly associated with grip strength. To be specific, middle-aged women who lived alone in rural areas had the lowest grip strength compared to other middle-aged women. Additional analysis showed that middle-aged women who lived alone in rural areas had risk factors, such as low education level, low income, or high depressive symptoms. It implies that middle-aged women living alone in rural areas may have physical health risks, so they might be in need of disease prevention. This study is meaningful in that it can provide reliable information on the latent welfare recipients by using representative panel data and applying weight values.

• Korean Journal of Heritage: History & Science
• /
• v.50 no.3
• /
• pp.110-125
• /
• 2017

The purpose of this study is to investigate the constructional facts and the operational features of Hamchunwon(含春苑), a wonyu(苑?, a royal garden) constructed in Dongbu(Eastern District) of the capital city of Hanyang. As the living quarters of the queen dowagers were scheduled for relocation after the construction of Changgyeonggung Palace(昌慶宮) during the reign of King Seongjong(成宗), it is presumed that the screening tree planting project discussed around tongmangcheo(通望處, a place allowing open view) was the original form of Dongbu Hamchunwon. Dongbu Hamchunwon was a longitudinal royal garden built in the area across the section from Wolgeunmun Gate(月覲門) to Seoninmun Gate(宣仁門), which were both attached to the east side walls of Changgyeonggung Palace. The area corresponds to the west side area of the newly built main building of Seoul National University Hospital today. During the Joseon Dynasty, only royal gardens built within a palace were referred to as geumwon(禁苑, a palace garden). But Dongbu Hamchunwon which was built outside a palace was recognized as a symbolic and hierarchical space comparable to geumwon. The site location of Donbu Hamchunwon was an important place that corresponded to Naecheongnyong(內靑龍) according to Hanyang's geomancy, and large-scale public works were prohibited in order to protect the vein of Naecheongnyong. During the reign of King Injo(仁祖), part of Dongbu Hamchunwon was partitioned as a ranch. The area around the ranch was called Madongsan(馬東山) and Bangmawon(放馬苑) and was an open space used for rest and pleasure (amusement). In the early days of Hamchunwon's construction, fast growing trees were planted to screen the view to Changgyeonggung Palace. However, after the construction of Gyeongmogung Shrine(景慕宮), a broad scale tree planting project was undertaken to complement Naecheongnyong's vapor of the earth. In particular, after the construction of Yugeunmum Gate(?覲門) and Yucheommun Gate(?瞻門) during the reign of King Jeongjo(正祖), Dongbu Hamchunwon functioned as a key point on the King's progress for paying respects to the ancestors, which followed the route of Palace(Changgyeonggung)-Wonyu(Hamchunwon)-Ancestral Shrine(Gyeongmogung).

• Korean Journal of Family Social Work
• /
• no.58
• /
• pp.5-36
• /
• 2017

This study aims to empirically analyze whether the women's cognitive attitude toward gender role, which is formed through social norms, enforces the gender division of housework. In this study, 4,435 married women aged 18-59 years from the 5th wave dataset of Korean Longutudinal Survey of Women and Family Data were selected for analysis. Using the Structural Equation Model(SEM), we examine the direct effect of "attitude toward behavior" and "subjective norm" on the domestic working hours and whether those two independent variables, such as "attitude toward behavior" and "subjective norm," influence the mediator variable "Behavior Intention" which in turn affect the dependent variable. The study reveals that "attitude toward the gender division of housework" has a statistically significant direct effect on the domestic working hours as well as an indirect effect operating through "behavior intention." And"subjective norm "has only a statistically significant indirect effect on the domestic working hours, operating through "behavior intention." Despite the fact that many women are now aware that various work-life balance policies are avaliable to mitigate the gender inequality of domestic works, it is proven that the gender division of housework becomes worse. The reason behind this is not only because there exist some problems in implementing the institutions themselves, but also because women's deeply internalized self-perception of gender role based on the traditional patriarchal culture somehow exacerbates the gender division of housework. Hence, in order to instill a progressive change in gender division of housework, it is important for women to try to change the way they perceive the stereotypical gender roles as well as for men to treat women equally.

• Korean Journal of Ecology and Environment
• /
• v.51 no.4
• /
• pp.268-286
• /
• 2018

The eutrophication and algal blooms by harmful cyanobacteria (CyanoHAs) and freshwater redtide (FRT) that severely experiencing in typical regulated weir system of the Nakdong River are one of the most rapidly expanding water quality problems in Korea and worldwide. To compare with the factors of rainfall, hydrology, and dominant algae, this study explored spatiotemporal variability of the major water environmental factors by weekly intervals in eight weir pools of the Nakdong River from January 2013 to July 2017. There was a distinct difference in rainfall distribution between upstream and downstream regions. Outflow discharge using small-scale hydropower generation, overflow and fish-ways accounted for 37.4%, 60.1% and 2.5%, respectively. Excluding the flood season, the outflow was mainly due to the hydropower release through year-round. These have been associated with the drawdown of water level, water exchange rate, and the significant impact on change of dominant algae. The mean concentration (maximum value) of chlorophyll-a was $17.6mg\;m^{-3}$ ($98.2mg\;m^{-3}$) in the SAJ~GAJ and $29.6mg\;m^{-3}$ ($193.6mg\;m^{-3}$) in the DAS~HAA weir pools reaches, respectively. It has increased significantly in the downstream part where the influence of treated wastewater effluents (TWEs) is high. Indeed, very high values (>50 or $>100mg\;m^{-3}$) of chlorophyll-a concentration were observed at low flow rates and water levels. Algal assemblages that caused the blooms of CyanoHAs and FRT were the cyanobacteria Microcystis and the diatom Stephanodiscus populations, respectively. In conclusion, appropriate hydrological management practices in terms of each weir pool may need to be developed.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.21 no.1
• /
• pp.201-210
• /
• 2019

Recently, due to the efforts to mitigate traffic congestion and expansion of space efficiency, the construction of underground roads has been increased in big-scale cities. Since tunnels in the city have a higher chance for a fire leading to a great tragedy during a severe traffic jam than mountain tunnels, it is highly likely that it will be constructed as a tunnel, having a small cross section, for small vehicles. However, if they are constructed as such small-vehicle tunnels, it would be possible to reduce the design fire intensity while the concentration of harmful gases would increase due to a reduction in the small cross sectional area, led by a decrease in the tunnel height. In this study, behaviors of fire smoke by the installation interval and format of large-scale exhaust-gas ports were examined and compared in the analysis of temperatures and CO concentrations of a tunnel and its results were as the following. Although there were no significant differences in the smoke spreading distance between installation intervals, but in this study, 100 m was found to be the most effective installation interval. The smoke exhaustion performance was found to be excellent in the order of $4m{\times}3m$, $6m{\times}2m$, and $3m{\times}2m$ (2 lane) of the smoke spreading distance. Although there was no significant difference in the smoke spreading distance between formats of large-scale exhaust-gas ports, it was found that the smoke spreading distance was larger than other cases when it was $3m{\times}2m$ in the fire growing process. The analysis of smoke spreading distances by the aspect ratio showed that a smoke spreading distance was shorted when its the smoke spreading distance was found to be shorter when its traverse distance was relatively longer than its longitudinal distance.

• Journal of Nutrition and Health
• /
• v.54 no.2
• /
• pp.139-151
• /
• 2021

Purpose: This study examines the correlation between fish consumption and the risk of mild cognitive impairment in the elderly living in rural areas. Methods: The Yangpyeong cohort data collected from Yangpyeong in July 2009 and August 2010 was used as the data set. Adults greater than or equal to 60 years who have completed the Korean version of the Mini-Mental State Examination (MMSE-KC) were selected for the study. After excluding participants with less than 500 kcal of energy intake (n = 2), a total of 806 adults were enrolled as the final subjects. Cognitive function was assessed using the MMSE-KC, and dietary intake was collected using the quantitative food frequency questionnaire comprising 106 foods or food groups. Results: The educational level, proportion of people who exercise, fruits and vegetable intake, and energy intake, tended to increase with fish intake among men, while increasing age resulted in decreased fish consumption. Among women, the educational level, proportion of subjects who exercise, proportion of subjects currently taking dietary supplements, fruits and vegetable intake, and energy intake, tended to increase with fish consumption, whereas increasing age showed decreasing fish consumption. Increased fish intake resulted in a higher MMSE-KC score after adjusting for the confounding variables in women (p for trend = 0.016), but no significant trend was observed between fish intake and MMSE-KC score in men. Fish intake was inversely related to the risk of mild cognitive impairment after adjusting for covariates in women (Q1 vs. Q4; odds ratio, 0.46 [0.23-0.90]; p for trend = 0.009). Conclusion: This study determined that increased fish consumption is correlated with reduced risk of mild cognitive impairment in the female elderly. Further longitudinal studies with larger samples are required to determine a causal relationship between fish intake and cognitive function.