• Kyungpook Mathematical Journal
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• v.62 no.4
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• pp.769-772
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• 2022

Given a prime number p and a natural number m not divisible by p, we propose the problem of finding the smallest number r₀ such that for r ≥ r₀, every group G of order p^rm has a non-trivial normal p-subgroup. We prove that we can explicitly calculate the number r₀ in the case where every group of order p^rm is solvable for all r, and we obtain the value of r₀ for a case where m is a product of two primes.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.3
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• pp.65-74
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• 2016

The Korean resident registration number has been used since 1962 as a personal identification number. The Korean government assigns this number to each korean citizen and it is not able to be changed. In 2000s, as the Internet was rapidly spreaded out, personal information such as the Korean resident registration number, name, home address, and phone number was leaked. The companies provide diverse internet service while collecting personal information. However, personal information was sometimes leaked because of hacking, poor information management and so on. As s results, some of citizens asked government and court of Korea to change the Korean resident registration number because they suffered material damage and emotional distress. The constitutional court decided to be able to change the number from 2018. In this study, the Korean resident registration number which is possible to change, serial number, public certificate, I-PIN, and My-PIN were analyzed comparatively. In addition, considerations when the Korean resident registration number was changed were discussed. The public certificate and I-PIN were appropriate to the case of on-line Korean resident registration number. The Korean resident registration number, serial number, My-PIN were appropriate to the case of off-line Korean resident registration number. Lastly, it would be efficient to manage the Korean resident registration number separately such as on-line and off-line.

• Management Science and Financial Engineering
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• v.13 no.2
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• pp.47-77
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• 2007

This paper considers a scheduling problem where a customer orders multiple products(jobs) from a production facility. The objective is to minimize the sum of the order(batch) completion times. While a machine can process only one job at a time, multiple machines can simultaneously process jobs in a batch. Although each job has a unique processing time, we consider the case where batch processing times are identical. This simplification allows us to develop heuristics with improved performance bounds. This problem was motivated by a real world problem encountered by foreign electronics manufacturers. We first establish the complexity of the problem. For the two parallel machine case, we introduce two simple but intuitive heuristics, and find their worst case relative error bounds. One bound is tight and the other bound goes to 1 as the number of orders goes to infinity. However, neither heuristic is superior for all instances. We extend one of the heuristics to an arbitrary number of parallel machines. For a fixed number of parallel machines, we find a worst case bound which goes to 1 as the number of orders goes to infinity. Then, a tighter bound is found for the three parallel machine case. Finally, the heuristics are empirically evaluated.

• The Journal of Korean Academic Society of Nursing Education
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• v.20 no.2
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• pp.321-331
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• 2014

Purpose: The purpose of this study was to investigate the effects of case management service for hypertensive elderly patients through the customized visiting home health care program. Method: Non-equivalent control group pretest-posttest design was employed. Data were collected from April 2007 to January 2009. Among a total of fifty subjects, 25 subjects were belonged to the case management group and the others were belonged to the general management group. Results: 1) In experimental group, significant increasing rate of number of people within normal blood pressure by time, but no significant increasing rate of number of people within normal blood neutral fat, total cholesterol, HDL, & LDL. 2) In experimental group, the score of knowledge about disease and healthy life practice were increased on 8 week period but decreased on follow up period. Number of people within normal blood HDL and mean score of healthy life practice were significantly higher than control group on follow up period. Conclusion: Case management service was effective on controlling blood pressure but partly effective on blood lipid, knowledge about disease, and healthy life practice in hypertensive patients. Further study is needed to conduct a periodic re-evaluation of the effect of case management and to verify an optimal interval to provide the case management service.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.133-141
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• 2001

Since the computing environment changes very rapidly, the estimation of software effort is very difficult because it is not easy to collect a sufficient number of relevant cases from the historical data. If we pinpoint the cases, the number of cases becomes too small. However is we adopt too many cases, the relevance declines. So in this paper we attempt to balance the number of cases and relevance. Since many researches on software effort estimation showed that the neural network models perform at least as well as the other approaches, so we selected the neural network model as the basic estimator. We propose a search method that finds the right level of relevant cases for the neural network model. For the selected case set. eliminating the qualitative input factors with the same values can reduce the scale of the neural network model. Since there exists a multitude of combinations of case sets, we need to search for the optimal reduced neural network model and corresponding case, set. To find the quasi-optimal model from the hierarchy of reduced neural network models, we adopted the beam search technique and devised the Case-Set Selection Algorithm. This algorithm can be adopted in the case-adaptive software effort estimation systems.

• Journal of Chest Surgery
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• v.12 no.4
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• pp.312-317
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• 1979

1] During the period of Jan. 1959, to Aug. 1979, 47 patients of paragonimiasis have been treated in the department of Chest Surgery. 2] The total number of patients who has been admitted and treated in the department of Chest Medicine are 262 and annual distribution of number of patients has been decreased. However, since 1964, the number of patients has been stationary. On the other hand, the total number of patients who has been admitted and treated surgically in the department of Chest Surgery are 47 and the annual distribution of number of patients has not been decreased. 3] The peak age incidence lies in fourth decade [34%], and over halves of patients is in third to fifth decade. Male to female is 8.4 to 1. 4] The symptoms, which are mainly cough, chest pain, dyspnea and blood tinged sputum, developed mostly in two to five years after infestation by Paragonmius westermani. 5] Sputum tests for eggs of Paragonimus westermani were positive in 16 out of 43 patients [37%]. The 93% of patients were positive in skin test for Paragonimus westermani. The patients with negative skin test were 7%, but sputum or stool examination for Paragonimus westermani`s eggs were positive in these negative group of skin test. 6] Chest roentgenogram revealed pleural effusion [41 cases], hydropneumothorax [1 case], atelectasis [1 case] and mediastinal mass [1 case]. 7] All patients were preoperatively treated with Bithionol. The mode of surgery were decortication only [31 cases], pleuropneumonectomy [3 cases], decortication & lobectomy [2 cases], decortication & closure of bronchial fistula [1 case], thoracentesis [1 case] and postural drainage [1 case]. 8] Paragonimiasis is primarily medical disease and well treated by the administration of Bithionol. But the delayed diagnosis and missed diagnosis, especially as pulmonary tuberculosis, make the disease aggravated and chronic. Subsequently, surgical treatment is infrequently required. Chronic empyema due to Paragonimus westermani is much benign than tuberculous empyema thoracis.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.1
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• pp.1-13
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• 2006

In this paper we consider a design problem of a cyclic queueing network with two stages, each with a local buffer of limited capacity. Based on the theory of reversibility and product-form solution, we derive the throughput function of the network as a key performance measure to maximize. Two cases are considered. In case each stage consists of a single server, an optimal allocation policy of a given buffer capacity and work load between stages as well as the optimal number of customers is identified by exploiting the properties of the throughput function. In case each stage consists of multiple servers, the optimal policy developed for the single server case doesn't hold any more and an algorithm is developed to allocate with a small number of computations a given number of servers, buffer capacity as well as total work load and the total number of customers. The differences of the optimal policies between two cases and the implications of the results are also discussed. The results can be applied to support the design of certain manufacturing and computer/communication systems.

• Journal of the Korean Society of Combustion
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• v.10 no.3
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• pp.34-41
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• 2005

Hydrogen safety is one of the key technical issue with growing attention on utilization of hydrogen energy. This study is aimed to predict behavior of momentum-controlling buoyant jet and flame caused by hydrogen leakage from a high pressured tank. Approximate solutions were derived for the case of turbulent buoyant jet and diffusion flame in still air. In case of hydrogen jet with low Froude number (100-4000), computed jet trajectories were compared with experimental data and showed good agreement with them. Jet and flame trajectories and flame length of hydrogen are predicted and compared with the buoyant flame of propane. The results well show that buoyancy is dominant in the range of low Froude number, while initial momentum is dominant in the range of high Froude number. That effect is more distinct for hydrogen flame than the case of propane.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.85-91
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• 2001

Biological treatment of benzene and toluene contaminated soil was investigated in laboratory microcosm of 16 different types for degrading benzene and toluene by indigenous bacteria. At the experimental conditions of the microcosms fast degrading benzene and toluene, moisture contents were 30% and 60% in a soil gap and content of powdered-activated carbon(PCA) for adhesion of benzene and toluene-degrading bacteria was 1% in total soil mass. At the conclusion of the shifted bacteria community, Case 6 and case 7 were operated until 10 days, and then the total cell number and the number of benzene and toluene degrading bacteria were investigated. The total cell number of Case 6 and Case 7 increased 488 fold and 308 fold of total indigenous cell, respectively. The number of benzene and toluene degrading bacteria increased and maintained the percentages occupied in pre-operating microcosm. Species of benzene and toluene degrading bacteria in microcosm changed from species of Gram negative bacteria to Gram positive bacterial species after soil exposed to benzene and toluene.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.207-214
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• 2005

Hydrogen safety is one of the key technical issue with growing attention on utilization of hydrogen energy. This study is aimed to predict behavior of momentum-controlling buoyant jet and flame caused by hydrogen leakage from a high pressured tank. Approximate solutions were derived for the case of turbulent buoyant jet and diffusion flame in still air. In case of hydrogen jet with low Froude number (100-4000), computed jet trajectories were compared with experimental data and showed good agreement with them. Jet and flame trajectories and flame length of hydrogen are predicted and compared with the buoyant flame of propane. The results well show that buoyancy is dominant in the range of low Froude number, while initial momentum is dominant in the range of high Froude number. That effect is more distinct for hydrogen flame than the case of propane.