• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권5호
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• pp.1390-1411
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• 2024

Underwater Wireless Sensors Networks (UWSNs) are deployed in remotely monitored environment such as water level monitoring, ocean current identification, oil detection, habitat monitoring and numerous military applications. Providing scalable and efficient routing is very challenging in UWSNs due to the harsh underwater environment. The biggest difficulties are the nodes inherent movement due to water current, long delay in data transmission, low bandwidth of the acoustic signal, high error rate and energy scarcity in battery powered nodes. Many routing protocols have been proposed to solve the aforementioned problems. There are three broad categories of routing protocols namely depth based, energy based and vector-based routing. Vector Based Forwarding protocols perform routing through virtual pipeline by defining their radius which give proper direction to packets communication. We proposed a routing protocol termed as Path-Oriented Energy Scaled Expanded Vector Based Forwarding (PESEVBF). PESEVBF takes into account all parameters; holding time, the source nodes packets routing path and void holes creation on the second hop; PESEVBF not only considers the packet upward advancement but also focus on density of the forwarded nodes in terms of number of potential forwarding and suppressed nodes for path selection. Node selection in resultant holding time is based on minimum Path Factor (PF) value. Moreover, the suppressed node will be selected for packet forwarding to avoid the void holes occurrences on the second hop. Performance of PESEVBF is compared with other routing protocols using matrices such as energy consumption, packet delivery ratio, packets dropping ratio and duplicate packets creation indicating considerable performance improvement.

• Journal of Korean Neurosurgical Society
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• 제67권1호
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• pp.6-13
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• 2024

The integrity of the high cervical spine, the transition zone from the brainstem to the spinal cord, is crucial for survival and daily life. The region protects the enclosed neurovascular structure and allows a substantial portion of the head motion. Injuries of the high cervical spine are frequent, and the fractures of the C2 vertebra account for approximately 17-25% of acute cervical fractures. We review the two major types of C2 vertebral fractures, odontoid fracture and Hangman's fracture. For both types of fractures, favorable outcomes could be obtained if the delicately selected conservative treatment is performed. In odontoid fractures, as the most common fracture on the C2 vertebrae, anterior screw fixation is considered first for type II fractures, and C1-2 fusion is suggested when nonunion is a concern or occurs. Hangman's fractures are the second most common fracture. Many stable extension type I and II fractures can be treated with external immobilization, whereas the predominant flexion type IIA and III fractures require surgical stabilization. No result proves that either anterior or posterior surgery is superior, and the surgeon should decide on the surgical method after careful consideration according to each clinical situation. This review will briefly describe the basic principles and current treatment concepts of C2 fractures.

• 수산해양기술연구
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• 제60권3호
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• pp.290-299
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• 2024

This study attempted to solve the problem that the current safety education contents of Korean fishing vessels are not consistent with the STCW-F Convention and do not properly reflect the actual operating environment of the fishing vessels. Despite the reinforced duty of safety education for fishing vessels after the Ferry Sewol accident, the problem has been pointed out that the effectiveness is still low due to merchant-oriented education contents and uniform education methods. Therefore, this study compared and analyzed laws related to safety education for fishing vessels and the STCW-F Convention, and derived improvement measures by collecting voices from the field through a survey of fishing vessels. As a result of the study, it was confirmed that the current fishing vessel safety education does not take into account the reality of fishing such as fishing vessel type, navigation distance, and ship output, and that the core curriculum required by STCW-F Convention is omitted. In addition, it was found that education content on major accident types that frequently occur along the coast was also insufficient. In order to improve this, this study proposes to re-establish the target of safety education for fishing vessels based on STCW-F Convention related to fishing vessels, and to prepare a segmented education system by reorganizing the training contents to suit reality. In addition, the need to clearly distinguish the education of merchant and fishing vessels through the revision of the Seafarers Act and the Ship Employees Act was suggested, and to establish a safety education system for fishing vessels that meets STCW-F Convention and domestic conditions.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제25권1호
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• pp.1-12
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• 2023

Objective: Although chronic carotid artery occlusion seems to be associated with significant risk of ischemic stroke, revascularization techniques are neither well established nor widespread. In contrast, extracranial-intracranial bypass is common despite the lack of evidence regarding neurological improvement or prevention of ischemic events. The aim of current review is to evaluate the effectiveness of various methods of recanalization of chronic carotid artery occlusion. Methods: Comprehensive literature search through PubMed, Scopus, Cochrane and Web of Science databases performed. Various parameters were assessed among patients underwent surgical, endovascular and hybrid recanalization for chronic carotid artery occlusion. Results: 40 publications from 2005 to 2021 with total of more than 1300 cases of revascularization of chronic carotid artery occlusion have been reviewed. Further parameters were assessed among patients underwent surgical, endovascular and hybrid recanalization for chronic carotid artery occlusion: mean age, male to female ratio, mean duration of occlusion before treatment, rate of successful recanalization, frequency of restenosis and reocclusion, prevalence of ischemic stroke postoperatively, neurological or other symptoms improvement and complications. Based on proposed through reviewed literature indications for revascularization and predictive factors of various recanalizing procedures, an algorithm for clinical decision making have been formulated. Conclusions: Although treatment of chronic carotid artery occlusion remains challenging, current literature suggests revascularization as single option for verified neurological improvement and prevention of ischemic events. Surgical and endovascular procedures should be taken into account when treating patients with symptomatic chronic carotid artery occlusion.

• 보건교육건강증진학회지
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• 제31권3호
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• pp.51-61
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• 2014

Objectives: The purpose of this study was to identify the effects of job characteristics on smoking, and the mediating effects of job stress between job characteristics and smoking among elderly workers. Methods: This study employed data from the Korean Longitudinal Study of Ageing, and a total of 778 older workers were used for analysis. Current smoking status, job stress, job characteristics including physical job demands, job demands related to contents, working days, regularity of working hour, satisfaction with income, and sociodemographic factors were analyzed. Descriptive analysis, t-tests, chi-square test, multiple linear regression, and logistic regression were used for analysis. Results: Results showed that physical job demands and regularity of working hours were significant predictors of smoking of elderly workers. The higher level of physical job demands and regular working-hour increased the risk of smoking. Also, physical job demands, job demands related job contents, and income satisfaction directly impacted on job stress. However, job stress did not mediate the relationship between job characteristics and smoking. Conclusions: The findings suggest that smoking interventions for older workers should take into account job characteristics. Implications for practice and future study directions are discussed.

• 한국시스템다이내믹스연구
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• 제8권2호
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• pp.83-114
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• 2007

The Korean defense industry was brought up in the government policy since 1970's. The important parts of defense industrial technologies have not been developed, and usually introduced from overseas. Moreover, the development of advanced technologies was not actively stimulated or pursued, consequently shaping the current structure of the defense industry which lacks global competitiveness due to the dearth of high technologies necessary for high-technology weapons. This research analyzes the systems of the Korean defense industry through a systems thinking approach in order to understand the whole mechanism and to find ways to improve the defense industry. Finding some leverages is the main purpose of systems thinking, that yields desirable results with a little effort. The three policy leverages are: (1) the policy for timely fielding; (2) the R&D investment for development and production of domestic high-technology weapons; and (3) the policy measures for exports. The research findings will contribute to the invigorating and developing the Korean defense industry by providing policy-makers and acquisition practitioners with systematic understanding and insight into the dynamics of the defense industry for them to make and execute efficient policies taking into account the Korean overall defense industry.

• 의료법학
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• 제9권2호
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• pp.339-382
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• 2008

Medical information is one of significant private information that includes in-dividual's own diverse information. Once opened, it exposes one's health condition and medical history to a third party, which could bring about serious troubles. On this account, the third parties are of much concerns about the information. If medical information collected through various routes is used with another purpose, oilier than the initial intention, it might cause serious results beyond one's control. Thus, it is essential to keep the information confidential. Also, the discrimination based on the medical information ought to be banned because it is likely to happen that exposed information socially stigmatizes a person, being discriminated in a work place or a school when he/she is employed or gets an insurance. In the current system, only medical institutions are responsible for protecting or securing medical records. Despite the information technology development and the increased interests in medical information, there are quite a few limitations in legal, technical, and administrative aspects. All kinds of organizations, involved in collecting and using the information, as well as medical institutions primarily producing and managing it should share the responsibilities.

• 대한화학회지
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• 제37권2호
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• pp.213-219
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• 1993

들뜬 rhodamine B로부터 박막반도체 $SnO_2$의 전도띠로 주입되는 광전류를 여러 가지의 초감응체가 존재하는 용액에서 시간에 따라 조사하였다. ascorbic acid를 초감응체로 쓰면 그것의 농도, 용액의 pH, 그리고 $SnO_2$에 걸어주는 전위 등이 증가함에 따라 광전류가 대체로 증가하였으나, 전위가 노팡짐에 따라 암전류도 증가하였다. 반면에 KI를 초감응제로 사용하면 낮지만 비교적 안정한 전류를 보여주었다. 용매효과를 포함하여 이들 광감응전류를 증가시키는 원인을 규명해 보았다.

• Agricultural and Biosystems Engineering
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• 제3권1호
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• pp.44-54
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• 2002

A brief review of current status in the field of agricultural spray and future research challenges are presented. Researches on the pesticides sprays, pollen sprays, postharvest sprays, and biological control agent sprays among the various applications of agricultural spray were selected and reviewed. In the agrochemical sprays, the techniques to increase the deposition such as electrospray and reduce the drift such as introductions of drift retardants and of mechanical means are reviewed. The introduction of mechanical means includes low drift, air-assisted, air inclusion, shield or shroud assisted and pulse flow nozzles. For flat fan nozzles, the data of breakup length and thickness of liquid sheet are essential to understand the atomization processes and develop the transport model to target In the air-assisted spray technology to reduce drift, further works on the effect of application height on drift and air assistance on droplet size should be followed. In addition, methods for quantifying the included air in the air inclusion techniques are required. The atomization characteristics of biopesticides spray are not being elucidated and the formulations of biopesticides should be taken into account the spray characteristics of existing nozzle and sprayer. A few researches on the droplet size of fallout can be found in the literature. A combined technology with electrostatic method into one of method for the reduction of drift may be an effective strategy for increasing deposition and reducing drift. Only an integrated approach involving all stakeholders such as engineers, chemists, and biologists, etc. can result in improved application of agricultural spray.

• 한국해안해양공학회지
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• 제3권1호
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• pp.54-64
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• 1991

현지해안의 표사이동량을 정확히 예측하기 위해서는, 표사이동의 주외력요소(agitation force)인 다방향불규칙 파랑의 천수변형 특성 및 그들에 의해서 발생하는 표사수송 흐름으로서의 해빈류에 대해서 충분히 파악해 둘 필요가 있다. 그러나, 현재 제안되어져 있는 연안류 및 이안류를 포함하는 해빈류 model은 대부분 규칙파 이론에 근거를 두고 파랑특성을 표현하고 있기 때문에 파랑의 불규칙성 및 방향분산성을 고려한 해빈류에 대한 연구는 극히 제한되어져 있다. 본 연구는 다방향불규칙 파랑에 의한 연안유속의 산정에 관한 기초적 연구로서, 주로 파별해석법에 의한 수치계산법을 제안함과 동시에 그들의 수치해석결과를 평면수리실험과 비교함으로써 그 타당성을 검토하였다.