• The KIPS Transactions:PartA
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• v.11A no.2
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• pp.195-202
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• 2004

This paper introduces the design or parallel Pipeline high-speed analog-to-digital converter(ADC) for the high-resolution video applications which require very precise sampling. The overall architecture of the ADC consists of 4-channel parallel time-interleaved 10-bit pipeline ADC structure a]lowing 200MSample/s sampling speed which corresponds to 4-times improvement in sampling speed per channel. Key building blocks are composed of the front-end sample-and-hold amplifier(SHA), the dynamic comparator and the 2-stage full differential operational amplifier. The 1-bit DAC, comparator and gain-2 amplifier are used internally in each stage and they were integrated into single switched capacitor architecture allowing high speed operation as well as low power consumption. In this work, the gain of operational amplifier was enhanced significantly using negative resistance element. In the ADC, a delay line Is designed for each stage using D-flip flops to align the bit signals and minimize the timing error in the conversion. The converter has the power dissipation of 280㎽ at 3.3V power supply. Measured performance includes DNL and INL of +0.7/-0.6LSB, +0.9/-0.3LSB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.922-929
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• 2005

This paper proposes an adaptive pilot beacon equipment for mobile communication systems based on direct spread spectrum technology which generates the pilot channel for handoff between base stations by using the information acquired from the downstream wireless signal regarding the overhead channel information. Such an adaptive pilot beacon equipment will enable low power operation since among the wireless signals, only the pilot channel will be generated and transmitted. The pilot channel in the downstream link of the CDMA receiver is used to acquire time and frequency synchronization and this is used to calibrate the offset for the beacon, which implies that time synchronization using GPS is not required and any location where forward receive signal can be received can be used as the installation site. The downstream link pilot signal searching within the CDMA receiver is performed by FPGA and DSP. The FPGA is used to perform the initial synchronization for the pilot searcher and DSP is used to perform the offset correction between beacon clock and base station clock. The CDMA transmitter the adaptive pilot beacon equipment will use the timing offset information in the pilot channel acquired from the CDMA receiver and generate the downstream link pilot signal synchronized to the base station. The intermediate frequency signal is passed through the FIR filter and subsequently upconverted and amplified before being radiated through the antenna.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.645-660
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• 1998

The purpose of this study was to make and ascertain a decision making process on the base of patient-oriented utilitarianism in the treatment of patients of chronic adult periodontitis. Fifty subjects were chosen in Yonsei Dental hospital and the other fifty were chosen in Severance dental hospital according to the selection criteria. Fifty four patients agreed in this study. NS group(N=32) was treated with scaling and root planing without any surgical intervention, the other S group(N=22) done with flap operation. During the active treatment and healing time, all patients of both groups were educated about the importance of oral hygiene and controlled every visit to the hospital. When periodontal treatment needed according to the diagnostic results, some patients were subjected to professional tooth cleaning and scaling once every 3 months according to an individually designed oral hygienic protocol. Probing depth was recorded on baseline and 18 months after treatments. A questionnaire composed of 6 kinds(hygienic easiness, hypersensitivity, post treatment comfort, complication, functional comfort, compliance) of questions was delivered to each patient to obtain the subjective evaluation regarding the results of therapy. The decision tree for the treatment of adult periodontal disease was made on the result of 2 kinds of periodontal treatment and patient's ubjective evaluation. The optimal path was calculated by using the success rate of the results as the probability and utility according to relative value and the economic value in the insurance system. The success rate to achieve the diagnostic goal of periodontal treatment as the remaining pocket depth less than 3mm and without BOP was $0.83{\pm}0.12$ by non surgical treatment and $0.82{\pm}0.14$ by surgical treatment without any statistically significant difference. The moderate success rate of more than 4mm probing pocket depth were 0.17 together. The utilities of non-surgical treatment results were 100 for a result with less than 3mm probing pocket depth, 80 for the other results with more than 4mm probing pocket depth, 0 for the extraction. Those of surgical treatment results were the same except 75 for the results with more than 4mm. The pooling results of subjective evaluation by using a questionnaire were 60% for satisfaction level and 40% for no satisfaction level in the patient group receiving nonsurgical treatment and 33% and 67% in the other group receiving surgical treatment. The utilities for 4 satisfaction levels were 100, 75, 60, 50 on the base of that the patient would express the satisfaction level with normal distribution. The optimal path of periodontal treatment was rolled back by timing the utility on terminal node and the success rate, the distributed ratio of patient's satisfaction level. Both results of the calculation was non surgical treatment. Therefore, it can be said that non-surgical treatment may be the optimal path for this decision tree of treatment protocol if the goal of the periodontal treatment is to achieve the remaining probing pocket depth of less than 3mm for adult chronic periodontitis and if the utilitarian philosophy to maximise the expected utility for the patients is advocated.

• Journal of Korean Neurosurgical Society
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• v.30 no.6
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• pp.705-710
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• 2001

Objective : Postoperative seizure is a well documented complication of aneurysm surgery. The purpose of the present study was to analyze risk factors for postoperative seizure. Methods : Between January 1990 and December 1996, we performed craniotomy for ruptured cerebral aneurysms in 321 patients. Among them 206 patients who could be followed up for more than 1 year(range, 1 to 4.6 years) were enrolled to present study. All patients were treated with anticonvulsants for 3 to 18 months postoperatively. We analyze the incidence of postoperative seizure in different sex and age groups, and risk factors associated with postoperative seizures following aneurysm rupture. For statistical processing chi-square test and Fisher's exact test were used. Results : In the follow-up period of 1 to 4.6 years(mean, 1.8 years) postoperative seizure appeared in 18 out of 206 patients(8.7%). Mean latency between the operation and the first seizure was 6 months(range, 3 weeks to 18 months). The age of the patients has significant influence on the risk of seizure, it occurred more often in younger patients(p =0.0014). Aneurysm location in the MCA was associated with a significantly a higher risk of seizure(p = 0.042). Eight patients(19%) out of 42 patients who suffered delayed ischemic neurologic deficit(DID) developed seizure. Delayed ischemic neurologic deficit was associated with significantly a higher risk of seizure(p =0.019). Infarct and hypertension were associated with significantly a higher risk of seizure(p <0.05). pre- or postoperative intracranial hematoma(intracerebral or epidural hematoma) was associated with significantly a higher risk of seizure(p <0.0001). H-H grade, Fisher grade, Glasgow Outcome Scale of patients and timing of operation after subarachnoid hemorrhage had no significant relation with the risk of seizure. Conclusion : Factors associated with the development of postoperative seizure were middle cerebral artery aneurysm, delayed ischemic neurologic deficit, infarct on late postoperative CT scan, hypertension, pre or postoperative intracranial hematoma(intracerebral or epidural hematoma). Identification of the risk factors may be help to focus the antiepileptic drug threapy in cases prone to develop seizures. Prospective evaluation is indicated.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.191-208
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• 2018

This paper focuses on the integration aspect of operators to determine an improvement strategy for the operating system to enhance competitiveness of Busan Port. This Study proposes the following alternatives: valuation standards for the integration of operators, the road map for the integration period, the scope and role setting of integrated operators' participation of Busan Port Authority(BPA), and the separation and linkage North Port and the New Port operators. First, the valuation standards for operator integration should be based on international standards. Additionally quantitative factors such as financial situation, business performance and participating companies' profitability, and the qualitative factors such as management ability, technology, and labor relations should be considered. Second, the timing of North Port's operator integration should be prioritized in the short term in conjunction with the commencement of its phase 2-4, 2-5, and 2-6. The integration of New Port operators should provide a road map for a relatively long-term perspective. Third, the participation of BPA' integrated operators should be considered in terms of publicity as a policy coordinator between terminals and by pursuing the profitability of entering into overseas business by fostering Korean global terminal operators. The scope and role of participation ensures that the experience and technology of the terminal operation business is maximized. Fourth, because physically intergrating the North Port' operator into a single corporate form is difficult, initially establishing a special purpose company to maximize the effect of the integrated operation is necessary. Then, the operators decided to convert to a holding company given the termination of the lease term contract with the State or BPA, and ultimately proposed a merger into a single corporation.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.542-547
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• 2002

Background: Postpneumonectomy empyema(PPE) is an infrequent but potentially life-threatening complication. To date, various surgical efforts have been made to manage this complication. We reviewed our 20-year surgical experience of PPE and long-term follow-up data. Material and Method: Total of 37 patients who were treated for PPE between fan, 1980 and Jun, 2000 were included. Various clinical factors such as micro-organism, operative method and timing, presence of bronchopleural fistula(BPF), underlying disease and fate of empyema cavity were retrospectively reviewed and analyzed. Result: Majority of patients(34) underwent Eloesser operation for effective drainage. There was only one operative mortality. The causative organisms were Staphylococcus species and Pseudomonas species in 46% BPF was found in 20 cases, among which spontaneous closures took place in 4 cases. The chest wall was closed in 40%(8/20) of patients with BPF, compared to 59%(10/17) without BPF. The closure rate was statistically better in patients without BPF(p=0.006). Even though the patients with benign disease showed higher closure rate(50%) than those with lung cancer (31%), the difference was not significant(p=0.25). Conclusion: Eloesser procedure was an effective method for initial drainage of PPE cavity with low operative mortality. Given the findings of low spontaneous closure rate of BPF, aggressive approach to close the BPF is mandatory to achieve the final goal of chest wall closure. It was found that majority of patients still left their chest cavity opened, even after controlling the active inflammation of the empyema cavity. More aggnessive approach for chest wall closure is recommended in all patents with benign disease and in selective patients with lung cancer if there is no evidence of recurrence at several years after the initial operation.

• Journal of the Daesoon Academy of Sciences
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• v.39
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• pp.137-174
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• 2021

The main theme of this paper centers on how to promote Three Major Works of Daesoon Jinrihoe, charity aid, social welfare, and education projects, during the unification period. Determining the best methods of promotion is crucial because the Three Major Works must be carried out after unification, and the works must remain based on the practice of the philosophy of Haewon-sangsaeng (the Resolution of Grievances for Mutual Beneficence). The idea of Haewon-sangsaeng is in line with the preface of the U.N. Charter and the aim of world peace. North Korean residents are suffering from starvation under their devastated economy, which is certain to face a crisis of materialistic deficiency during reunification. In this study, the peaceful unification of Germany, unification under a period of sudden changes in Yemen, and the militarized unification of Vietnam were taken as case studies to diagnose and analyze the conditions which would affect the implementation of the Three Major Works. These three styles of unification commonly required a considerable budget and other forms of support to carry out the Three Major Works. Especially if unification were to occur after a period of sudden changes, this would require solutions to issues of food, shelter, and medical support due to the loss of numerous lives and the destruction of infrastructure. On the other hand, the UNHCR model was analyzed to determine the implications of expanding mental well prepared and sufficiently qualified professionals, reorganizing standard organizations within complex situations, task direction, preparing sufficient relief goods, budgeting, securing bases in border areas with North Korea, and establishing networks for sponsorship. Based on this, eight detailed tasks in the field of system construction could be used by the operators of the Three Major Works to prepare for unification. Additionally, nine tasks for review were presented in consideration of the timing of unification and the current situation between South and North Korea. In conclusion, in the event of unification, the Three Major Works should not be neglected during the transition period. The manual "Three Major Works during the Unification Period" should include strategic points on organizational formation and mission implementation, forward base and base operation, security and logistics preparation, public relations and external cooperation, safety measures, and transportation and contact systems.

• Journal of Korea Water Resources Association
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• v.41 no.7
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• pp.711-723
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• 2008

In this study, Hydrologic regime alterations(magnitude, magnitude and duration of annual extreme, frequency and duration of high and low pulse, rate and frequency of water condition changes, Range of Variability Approach) were analyzed by using Indicators of Hydrologic Alterations at the 11 major multi-purpose dam. The analysis result of the magnitude of monthly water conditions during drought season, inflow was $6.38m^3/sec{\sim}39.84m^3/sec$ and outflow was $20.36m^3/sec{\sim}49.43m^3/sec$, was increased $1.84%{\sim}200.98%$. The analysis result of the magnitude of monthly water conditions during flood season, inflow was from $79.06m^3/sec{\sim}137.12m^3/sec$ and outflow was from $65.32m^3/sec{\sim}80.16m^3/sec$, was decreased from $18.19%{\sim}40.39%$. The analysis result of the magnitude and duration of annual extreme, 1-day minimum was increased $82.86%{\sim}2,950%$, but 1-day maximum was decreased $34.78%{\sim}83.96%$. The analysis result of the frequency and duration of high and low pulse, low pulse count was decreased $29.67%{\sim}99.07%$ and high pulse count was also decreased $4.6%{\sim}92.35%$ after dam operation. Hydrograph rise rate was decreased $15.84%{\sim}79.31%$ and fall rate was $1.97%{\sim}107.10%$. RVA of 1-day minimum was increased $0.60{\sim}2.67$, also RVA of 1-day maximum was decreased $0.50{\sim}1.00$.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.3
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• pp.127-150
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• 2020

A Basic Plan for the Promotion of Space Development (hereinafter referred to as "basic plan"), which prescribes mid- and long-term policy objectives and basic direction-setting on space development every five years, is one of the matters to be deliberated by the National Space Committee. Confirmed February 2018 by the Committee, the 3rd Basic Plan has a unique matter, compared to the 2nd Basic Plan. It is to construct "Korean Positioning System(KPS)". Almost every country in the world including Korea has been relying on GPS. On the occasion of the shooting down of a Korean Air flight 007 by Soviet Russia, GPS Standard Positioning Service has been open to the world. Due to technical errors of GPS or conflict of interests between countries in international relations, however, the above Service can be interrupted at any time. Such cessation might bring extensive damage to the social, economic and security domains of every country. This is why some countries has been constructing an independent global or regional satellite navigation system: EU(Galileo), Russia(Glonass), India(NaVic), Japan(QZSS), and China(Beidou). So does South Korea. Once KPS is built, it is expected to make use of the system in various areas such as transportation, aviation, disaster, construction, defense, ocean, distribution, telecommunication, etc. For this, a pan-governmental governance is needed to be established. And this governance must be based on the law. Korea is richly experienced in developing and operating individually satellite itself, but it has little experience in the simultaneous development and operation of the satellites, ground, and users systems, such as KPS. Therefore we need to review overseas cases, in order to minimize trial and error. U.S. GPS is a classic example.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.792-798
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• 2002

Although there is a controversy on the optimal timing for active infective endocarditis(IE), recently good results of early surgical intervention have been published. Herein, we analyzed the results of surgery for active IE according to the duration of preoperative antibiotic treatment. Material and Method : Retrospectively, we analyzed 51 patients who underwent operation for active IE at the department of thoracic and cardiovascular surgery of Samsung medical center from Mar. 1995 to Oct. 2001. Male to female ratio was 39:12, mean age of the patients was 44.5$\pm$17.8 years(range : 13~74). Infected valves were mitral valve in 17(33.3%), aortic valve in 15(29.4%), mitral and aortic valve in 12(23.5), and tricuspid valve in 5(9.8%) cases. Among them, prosthetic valve endocarditis was present in 10(19.6%) cases. Infecting organism was Staphylococcus in 19(37.3%), Streptococcus in 17(33.3%), Enterococcus in 3(5.9%), fungus in 3(5.9%), and other bacteria in 5(9.8%) cases. Organism was not isolated in 6(11.8%) cases, and two organisms were isolated in 4(7.8%) cases. Dividing these patients into two groups according to the duration of preoperative antibiotic treatment(A: less than 7 days, B: more than 8 days), we compared the surgical results between the two groups. Result : There were 16 cases in group A and 35 in group B. Annular reconstruction was performed in 10(62.5%) cases in group A and 10(28.6%) cases in group B, which has statistically significance(p＜0.05). There was one early death in group B. Forty nine patients(96.1%) except two were followed up with mean follow-up duration of 28.7 $\pm$ 23.6 months. Endocarditis was recurred in one in group A, and two in group B. Three late deaths occurred in group B. Recurrence rate and survival were not statistically different between the two groups. Conclusion : Early surgery for active IE showed good results as the result of that which was performed after prolonged antibiotic treatment; therefore, we believe that early surgery for active If could effectively eradicate the infection.