• Bulletin of the Korean Mathematical Society
• /
• v.37 no.4
• /
• pp.649-657
• /
• 2000

The 2-step competition graph of D has the same vertex set as D and an edge between vertices x and y if and only if there exist (x, z)-walk of length 2 and (y, z)-walk of length 2 for some vertex z in D. The 2-step competition number of a graph G is the smallest number k such that G together with k isolated vertices is the 2-step competition graph of an acyclic digraph. Cho, et al. showed that the 2-step competition number of a path of length at least two is two. In this paper, we characterize all the minimal acyclic digraphs whose 2-step competition graphs are paths of length n with two isolated vertices and construct all such digraphs.

• Proceedings of the Korea Contents Association Conference
• /
• 2005.11a
• /
• pp.210-218
• /
• 2005

Recently, customers can select various service providers using number portability according to given select options such as quality of service and fare organization. Therefore it is possible that subscriber maintenance and quality competition are converted to fare competition which is real competition concept. However, it is time that we need number portability between $2G{\rightarrow}3G$ for activating 3G services because some important issues are closed such as domestic number portability, WiBro service provider selection. In this paper, we proposed applying method and necessity of $2G{\rightarrow}3G$ number portability Also, we analyzed $2G{\rightarrow}3G$ number portability examples of domestic and foreign countries and domestic market situation about abstract of 3G mobile communication service and number portability introduction between $2G{\rightarrow}3G$ for 3G service activation appearing newly in this research.

• Korean Journal of Environmental Agriculture
• /
• v.14 no.2
• /
• pp.221-231
• /
• 1995

The objectives of the present study were to find out the differences in growth and weed competition of rice under the foggy and non-foggy condition, and finally, the fundamental data for the establishment of the paddy weed control system under the locational foggy regions. The research was carried out on tin trays ($0.12m^2$) in greenhouse equipped with an Auto Foggy System(SAE KI RTN Co.). The results are summarized as follows: Exp. I. Difference in rice growth under the foggy and non-foggy condition. 1. While the plant height was not affected, the number of tillers was decreased by the foggy condition. The ratio of the number of effective tiller, however, became higher under the foggy condition. 2. Due to the fog present, the heading rate was decreased and heading time was delayed. 3. The foggy condition did not affect the dry weight of rice straw whether they were grown under the foggy or non-foggy condition. However, yield components such as the number of ears, the number of grains per ear, thousand kernel weight and percentage of ripeness were reduced. Particularly, weights of perfect brown and unpolished rice were also decreased. Exp. II. Effect of the duration of competition between weed and rice grown under the foggy condition on the growth of rice plant. 1. There was no difference in the height of rice grown under a different duration of competition. There was a clear tendency that the number of tillers of rice grown under the foggy condition was decreased as the duration of competition was decreased. 2. When the duration of competition was longer than 60 days, the heading rate was decreased and the initiation of heading was also delayed by 2-4 days. 3. Under the foggy condition, the duration of competition for more than 40 days affected dry weight of rice straw and the difference in yield was greatest in the non-competition and competition for more than 40 days.

• Korean Journal of Weed Science
• /
• v.13 no.2
• /
• pp.151-158
• /
• 1993

This experiment was conducted in order to understand the intra-and the inter-competition of arrowhead, Sagittaria trifolia L., under the conditions of arrowhead monoculture and rice-mixed culture, respectively. In arrowhead monoculture, the infra-specific competition in both shoot length and floral axis number began at 10 plants per $0.5m^2$ and that in leaf number, leaf length, dry shoot weight and formated tuber number did at 5 plants per $0.5m^2$. In the inter-specific competition according to arrowhead density in the constant rice-mixed culture, the plant height and the tiller number of rice decreased at 15 and 5 plants of arrowhead per $0.5m^2$, respectively. The dry top weight and the formated tuber number of arrowhead decreased with increase of arrowhead density. In the inter-competition according to rice plant density in the constant arrowhead-mixed stands, the dry matter weight and the produced tuber number of arrowhead decreased with increase of rice plant density and the plant height and the tiller number of rice also did with that. In the different transplantation time of rice, the growth in arrowhead became less in order of late transplantation>standard one>early one and the plant height and the tiller number of rice became more in order of that by comparing the percentage of growth under the mixed culture to that under the arrowhead monoculture.

• KDI Journal of Economic Policy
• /
• v.34 no.2
• /
• pp.41-53
• /
• 2012

This paper investigates the effect of competition on innovative activity. In the research contest, the foremost reason for limiting entry into tournaments is to raise the level of contestant's effort and to make the firms compete so that high value of innovation will be procured. Thus, a sponsor (or government) needs to take account into effort-inducing effect as well as effort-reducing effect from competition when she restricts entry. In this paper, this competition effect will be analyzed for the model of procurement for innovation, and it is shown that the individual effort level is not monotonic to the number of contestants.

• STI Policy Review
• /
• v.6 no.1
• /
• pp.24-35
• /
• 2015

This research constructs a data set regarding competition policy through a comprehensive review of previous studies, and performs a meta-analysis to quantitatively assess the price effects of deregulation. A structural econometric model is used to eliminate possible biases from heterogeneity of the studies,such as in publication types and measurement methods. Four types of regulations that deter competition are characterized and three groups of industries are made for drawing practical implications. We fnd that deregulation to promote competition reduces prices by 0.23% and that these estimated price effects are more stable when we control for the publication types and measurement ways. Easing regulations that restrict consumers' choice is shown to be most effcient in promoting competition, lowering prices by 0.7%. This is followed by eliminating the limitation in the number of frms in the industry, with 0.2% price reduction. Overall, the network and service industries are shown to be more responsive to deregulation than the R&D industry. These results could shed light on policy implementation when a pro-competition policy is called for due to restrictive regulations in the corresponding industries.

• Health Policy and Management
• /
• v.6 no.2
• /
• pp.14-42
• /
• 1996

On rationale for government intervention is the failure of competition in the market. Health care markets are characterized by such unique aspects as information asymmetry, prevalence of insurance, and cost-increasing competition based on the adoption of costly medical technology. Therefore, government policy to guarantee a sufficient number of providers in markets may not lead to socially beneficisal outcomes such as higher quantity and lower price. This paper examines the unique nature of health services and its implications for competition, the evidence that competition may not reduce health care ex[enditures, and policy tools that government can use to encourage competition which contributes to supporting a sustainable health care system.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.8 no.1
• /
• pp.69-81
• /
• 1970

1. Four soybean varieties in pure stand and mixtures were grown in 20 competition treatments of genotypes at within-row spacings of 5, 10, 20, 40, and 80 cm and were investigated in 10 characters for different genotypes. 2. Yield, weight of 100 seeds, height, number of branches, pods per plant, and seeds per pod were highly significant for within-row spacing treatment. 3. There was no spacing treatment effect for number of nodes and days to flower. Maturity did not respond equally in four varieties for spacing effect. 4. Fruiting period was influenced by spacing treatment. Height and number of branches were increased as within-row spacings were increased. Seed yield per area was increased oppositely. 5. Difference between fertilizing and non-fertilizing treatment was not significant in this experiment. At 80 cm spacing no competition effect occurred for yield. 6. In the competition effect, Kumkang Daerip was strong competitor ani Chungbuck Back and Shelby were weak competitors. 7. The within-row spacing of uniformity in roder to increase yield per area was proved as 20 cm in this study. 8. Oil percent was increased as spacings were increased and protein percent was as spacings were decreased.

• Korean Journal of Weed Science
• /
• v.15 no.4
• /
• pp.270-277
• /
• 1995

The research was carried out in tray in greenhouse equipped with Auto Foggy Systems(SAE KI RIN Co.) and the results were summarized as follows. 1. The number of leaves and fresh weight of Chinese cabbage were not different, but the plant height was increased due to foggy condition. 2. Plant height was decreased in 40 and 60 days of weed competition by foggy condition, the number of leaves was not different. And, shoot fresh weight was decreased by in all the duration of weed competition under foggy condition. Especially, that was greater in 40 days. 3. The shoot fresh weight was decreased by pendimethaline and napropamide application under foggy condition. Also, the number of leaves was decreased at 60 days after transplanting by pendimethaline application under foggy condition. 4. Pendimethalin, napropamide and alachlor treatments were not different in the weeding efficacy between non-foggy and foggy conditions. Trifluraline showed lower weeding efficacy by seedling emergence of large crabgrass as the days of treatment got longer under foggy condition.

• Health Policy and Management
• /
• v.13 no.3
• /
• pp.129-147
• /
• 2003

This study is to grasp a trend of profitability classified by characteristics of hospitals and to analyze related factors. Subjects are 145 hospitals which have gotten the standardization audit by Korean Hospital Association during 1998-200l. Profitability was measured in the aspect of operation profit rate with operating margin to gross revenue as proxy variables. Independent variables were classified by general factors (ownership, number of beds, period of establishment, competition), financial factors (liabilities to total assets, current ratio, fixed ratio, total asset turnover, inventories turnover), and factors related to patient treatment (average length of stay, bed occupancy rate, new outpatient ratio, admission ratio of outpatients, number of patients per specialist, personnel costs per adjusted inpatient, administrative costs per adjusted inpatient). Hierarchical multiple regression analysis model was used in this study. As a result of hierarchical multiple regression analyzation of operating margin to gross revenue, adjustive $R^2$ of general factors was relatively more powerful. The factors had significant effect on operating margin to gross revenue were ownership(+), number of beds(+), competition(+), current ratio(+), fixed ratio(+), total asset turnover(+), personnel costs per adjusted inpatient(-).