• 자원리싸이클링
• /
• 제33권1호
• /
• pp.3-14
• /
• 2024

LED 산업은 기술의 발전과 에너지 절감 정책을 바탕으로 수요가 급증하면서 시장은 급격히 확대되고 있다. 그에 따라 지속적으로 축적되는 LED 폐자원의 효율적인 재활용이 사회적 관심으로 증가하고 있어 현재 LED 폐자원의 재활용 상황과 향후 나아갈 방향에 대해 고찰하였다. 현재 LED 폐자원의 재활용은 Ga 회수기술에 초점이 맞춰져 있어 전처리 및 고부가가치 소재의 농축/회수 등 통합적인 재활용 기술 개발이 요구되는 상황이다. 본 논문에서는 LED 폐자원의 현황 및 재활용 기술을 알아보고 향후 방향에 대해 제시하였다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제46권2호
• /
• pp.125-132
• /
• 2020

Objectives: The requirement for overnight hospital stay should be considered preoperatively according to patient-related factors, type of surgery, and anesthetic management plan. In this study, we aimed to define the major factors that influence consideration of overnight hospital stay in patients undergoing oral and maxillofacial (OMF) surgery in an operating room (OR) of a dental hospital in an outpatient setting. Materials and Methods: The records of patients who underwent oral procedures under general anesthesia between 2014-2017 were reviewed. Results: A total of 821 patients underwent oral procedures under general anesthesia; 631 of them underwent OMF surgery in the OR of a dental hospital, and 174 of these patients were hospitalized for overnight stay. There was no significant difference in the number of patients with comorbidities between the outpatient and hospitalized patient groups (P=0.389). The duration of surgery was longer in the hospitalized patient group (105.25±57.48 vs 189.62±82.03 minutes; P<0.001). Double-jaw (n=15; 310.00±54.21 minutes) and iliac crest grafting surgeries (n=59; 211.86±61.02 minutes) had the longest durations. Patients who underwent iliac crest grafting had the highest rates of hospitalization (79%). The overall recovery period was longer in outpatients (119.40±41.60 vs 149.83±52.04; P<0.001). Conclusion: Duration of surgery was the main determinant in considering whether a patient required overnight hospital stay. However, patients with an American Society of Anesthesiology physical status score <3 may be scheduled for OMF surgery in the OR of a dental hospital in an outpatient setting regardless of duration of surgery if overnight hospital stay is planned or an extended recovery period is provided until patients meet the discharge criteria.

• Korean Journal of Radiology
• /
• 제21권6호
• /
• pp.736-745
• /
• 2020

Objective: To identify the initial chest computed tomography (CT) findings and clinical characteristics associated with the course of coronavirus disease 2019 (COVID-19) pneumonia. Materials and Methods: Baseline CT scans and clinical and laboratory data of 72 patients admitted with COVID-19 pneumonia (39 men, 46.2 ± 15.9 years) were retrospectively analyzed. Baseline CT findings including lobar distribution, presence of ground glass opacities, consolidation, linear opacities, and lung severity score were evaluated. The outcome event was recovery with hospital discharge. The time from symptom onset to discharge or the end of follow-up (for those remained hospitalized) was recorded. Data were censored in events such as death or discharge without recovery. Multivariable Cox proportional hazard regression was used to explore the association between initial CT, clinical or laboratory findings, and discharge with recovery, whereby hazard ratio (HR) values < 1 indicated a lower rate of discharge at four weeks and longer time until discharge. Results: Thirty-two patients recovered and were discharged during the study period with a median length of admission of 16 days (range, 9 to 25 days), while the rest remained hospitalized at the end of this study (median, 17.5 days; range, 4 to 27 days). None died during the study period. After controlling for age, onset time, lesion characteristics, number of lung lobes affected, and bilateral involvement, the lung severity score on baseline CT (> 4 vs. ≤ 4 [reference]: adjusted HR = 0.41 [95% confidence interval, CI = 0.18-0.92], p = 0.031) and initial lymphocyte count (reduced vs. normal or elevated [reference]: adjusted HR = 0.14 [95% CI = 0.03-0.60], p = 0.008) were two significant independent factors that influenced recovery and discharge. Conclusion: Lung severity score > 4 and reduced lymphocyte count at initial evaluation were independently associated with a significantly lower rate of recovery and discharge and extended hospitalization in patients admitted for COVID-19 pneumonia.

• 정보처리학회논문지B
• /
• 제16B권3호
• /
• pp.233-238
• /
• 2009

자질 수가 적은 소규모 크기 문서들의 자동분류는 좋은 성능을 얻기 어렵다. 그 이유는 문서집단 전체의 자질 수는 크지만 단위 문서 내 자질 수가 상대적으로 너무 적기 때문에 문서간 유사도가 너무 낮아 우수한 분류 알고리즘을 적용해도 좋은 성능을 얻지 못한다. 특히 웹 디렉토리 문서들의 자동분류에서나, 디스크 복구 작업에서 유사도 평가와 자동분류로 연결되지 않은 섹터를 연결하는 작업에서와 같은 소규모 크기 문서의 자동분류에서는 좋은 성능을 얻지 못한다. 따라서 본 논문에서는 소규모 크기 문서의 자동분류에서의 문제점을 해결하기 위해 분류 사전작업으로, 예제기반 자질 필터링 방법 Relief-F알고리즘을 소규모 문서 내 자질 필터링에 적합한 ERelief-F 알고리즘을 제시한다. 또 비교 실험을 위해, 기존의 자질 필터링 방법 중 Odds Ratio와 정보이득, 또 Relief-F 알고리즘을 함께 실험하여 분류결과를 비교하였다. 그 결과, ERelief-F 알고리즘을 사용했을 때의 결과가 정보이득과 Odds Ratio, Relief-F보다 월등히 우수한 성능을 보였고 부적절한 자질도 많이 줄일 수 있었다.

• 가정과삶의질연구
• /
• 제29권6호
• /
• pp.9-25
• /
• 2011

This study was performed to explore the factors that affect debt-use intention of young defaulters. In addition, this study compares three models that predict the intention to use debt by young defaulters: the theory of reasoned action and two variations of it. Specifically, this study proposes an extended theory of reasoned action by introducing Ao in place of the cognitive structure in the theory of reasoned action. In addition, this study proposes Ao as an independent variable that acts on BI rather than a dependent variable. Self-administered questionnaires were completed by 196 young defaulters attending a credit management education session held by the Credit Counseling & Recovery Service in Kwang-ju, Korea. Based on the study, the conclusions are as follows: the extended theory of reasoned action as proposed in this article most suitably explained the intention to use debt by young defaulters. It was also found that young defaulters were affected by attitudes toward debt, attitudes toward using debt, and subjective norms. It is therefore suggested that an attitudinal message would change the behavior effectively for young defaulters. The findings appeared to support the usefulness of the extended theory of reasoned action and the role of Ao as an independent variable as proposed in this article to explain the intention to use debt by young defaulters. These findings have an important theoretical meaning in that they modify two existing attitude theories in the context of consumer behavior.

• 대한기계학회논문집B
• /
• 제33권6호
• /
• pp.403-410
• /
• 2009

This paper proposes a new approach to find the optimum ratios between sizes of the heat exchangers of the heat recovery steam generator (HRSG) system with limited size to maximize the efficiency of the steam turbine (bottom) cycle of combined cycle power plants (CCPP), but without performing the bottom cycle analysis. This could be achieved by minimizing the unavailable exergy (the sum of the destroyed and the lost exergies) resulted from the heat transfer process of the HRSG system. The present approach is relatively simple and straightforward because the process of the trial-and-error method, typical in performing the bottom cycle analysis for the system optimization, could be avoided. To demonstrate the usefulness of the present method, a single-stage HRSG system was chosen and the optimum evaporation temperature was obtained corresponding to the condition of the maximum useful work. The results show that the optimum evaporation temperature based on the present exergy analysis appears similar to that based on the bottom cycle analysis. Also shown is the dependency of size (NTU) ratios between the heat exchangers on the inlet gas temperature, which is another important factor in determining the optimum condition once overall size of the heat recovery steam generator is given. The present approach turned out to be a useful tool for optimization of the singlestage HRSG systems and can easily be extended to multi-stage systems.

• 자동차안전학회지
• /
• 제8권4호
• /
• pp.24-30
• /
• 2016

In Korea, the Vehicle Dismantler and Recycler industry is supervised by the Ministry of Land, Infrastructure and Transport under the Automobile Management Act. Also, Korean Automotive recycling businesses are supervised by the Minister of Environment under the Resource Recirculation Act. The main concern of the Minister of Environment is how the wastes from Dismantled vehicles will be environmentally removed, stored, treated, recycled or disposed. In 2000, the European Union (EU) adopted the End-of-Life Vehicles Directive (2000/53/EC) which required Members to ensure the collection, treatment and recovery of end-of-life vehicles (ELVs). The Directive, the most tightly regulated and precautionary legal systems, required that the last owner of a vehicle could drop off the ELV at an authorized treatment facility and that the producers of the ELV should pay the cost of the program. The adoption of the ELVs directive has led the development of Automotive Dismantler and Recycler networks to reuse, refurbish, remanufacture, recycle and recover parts and materials embedded in ELVs. Also, the ELVs directive which has had an insignificant impact on Korean manufacturers has strong presence in the European market and has been successfully externalized on them. The Korean manufacturers not only achieve the 85% recycling target set by the ELVs directive but also meet the Extended Producer Responsibility (EPR) which requires manufacturers to contribute dismantling process. In order to improve the Korean vehicle dismantling and recycling system, the Automobile Management Act and the Resource Recirculation Act should be harmonized. Particularly the roles of the Ministry of Land, Infrastructure and Transport and the Minister of Environment should be sharply divided. Like Japan, the ELV management needs to be highly centralized, regulated, and controlled by the ministry specialized in Vehicle, namely the Ministry of Land, Infrastructure and Transport and the sub organizations. Like EU Members, recovery, reuse, and recycling must be distinguished. Recovery is defined as the final productive use of the parts and materials embedded in ELVs, which includes reuse and remanufacture of parts and recycling of the other materials. Dismantling process and reuse and remanufacture of parts must be governed by the Ministry of Land, Infrastructure and Transport. For environmental recycling or disposal of waste materials, such as CFCs, glass and plastic material, and toxic substances, governmental financial support system should be in place.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권6호
• /
• pp.2148-2167
• /
• 2021

The proliferation of the Internet of Things (IoT) technologies and applications, especially the rapid rise in the use of mobile devices, from individuals to organizations, has led to the fundamental role of secure wireless networks in all aspects of services that presented with many opportunities and challenges. To ensure the CIA (confidentiality, integrity and accessibility) security model of the networks security and high efficiency of performance results in various resource-constrained applications and environments of the IoT platform, DDO-(data-driven operation) based constructions have been introduced as a primitive design that meet the demand of high speed encryption systems. Among of them, the TMN-family ciphers which were proposed by Tuan P.M., Do Thi B., etc., in 2016, are entirely suitable approaches for various communication applications of wireless mobile networks (WMNs) and advanced wireless sensor networks (WSNs) with high flexibility, applicability and mobility shown in two different algorithm selections, TMN64 and TMN128. The two ciphers provide strong security against known cryptanalysis, such as linear attacks and differential attacks. In this study, we demonstrate new probability results on the security of the two TMN construction versions - TMN64 and TMN128, by proposing efficient related-key recovery attacks. The high probability characteristics (DCs) are constructed under the related-key differential properties on a full number of function rounds of TMN64 and TMN128, as 10-rounds and 12-rounds, respectively. Hence, the amplified boomerang attacks can be applied to break these two ciphers with appropriate complexity of data and time consumptions. The work is expected to be extended and improved with the latest BCT technique for better cryptanalytic results in further research.

• Journal of Communications and Networks
• /
• 제6권4호
• /
• pp.362-375
• /
• 2004

An ad hoc network is a multi-hop wireless network. Its limited bandwidth and frequently changing topology require that its protocol should be robust, simple, and energy conserving. We have proposed PoolODMRP to reduce its control overhead greatly by its one-hop local route maintenance. However, PoolODMRP still has some shortcomings. In this paper, we propose PDAODMRP (passive data acknowledgement ODMRP) to extend PoolODMRP. Compared with PoolODMRP, PDAODMRP has the following contributions: (1) It knows the status of its downstream forwarding nodes by route information collected from data packets instead of BEACON signal of MAC layer; (2) it max simplifies the route information collected from data packets by pool nodes; (3) it adopts a dynamic local route maintenance to enforce its local route maintenance; (4) it adopts the route evaluation policy of NSMP (neighbor supporting multicast protocol). Compared with PoolODMRP, PDAODMRP has lower control overhead, lower data delivery delay, and lower data overhead.

• 대한치과의사협회지
• /
• 제21권12호통권175호
• /
• pp.991-995
• /
• 1983

A radicular cyst is a slowly-growing epithelial sac lining a pathologic cavity in the bone at the apex of a tooth. Large radicular cyst revealed by radiographic examination almost always appear to involved several teeth. The author observed a 31 year old woman with a labial swelling and palatal mucosal expansion of the maxillary anterior region. Radiographic examination indicated that the lesion extended from the left maxillary lateral incisor to the right lateral incisor. Cyst consisted of tan to gray yellow slightly firm to partly hard plaque like tissue measuring 3.4 x 2.2 x 0.3㎝. The author has treated the cyst by means of enucleation with apicoecomies of the involved teeth except the right central incisor. Recovery proceed satisfactorily and there were no clinical or radiologic signs of recurrence 8 months later.