• Clinical Endoscopy
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• v.56 no.2
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• pp.143-154
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• 2023

Advanced malignant hilar biliary obstruction (MHBO) with inaccessible papilla poses a significant challenge to endoscopists, as drainage of multiple liver segments may be warranted. Transpapillary drainage may not be feasible in patients with surgically altered anatomy, duodenal stenosis, prior duodenal self-expanding metal stent, and after initial transpapillary drainage, but require re-intervention for draining separated liver segments. Endoscopic ultrasound-guided biliary drainage (EUS-BD) and percutaneous trans-hepatic biliary drainage are the feasible options in this scenario. The major advantages of EUS-BD over percutaneous trans-hepatic biliary drainage include a reduction in patient discomfort and internal drainage away from the tumor, thus reducing the possibility of tissue or tumor ingrowth. With innovations, EUS-BD is helpful not only for bilateral communicating MHBO but also for non-communicating systems with bridging hilar stents or isolated right intra-hepatic duct drainage by hepatico-duodenostomy. EUS-guided multi-stent drainage with specially designed cannulas and guidewires has become a reality. A combined approach with endoscopic retrograde cholangiopancreatography for re-intervention, interventional radiology, and intraductal tumor ablative therapies has been reported. Stent migration and bile leakage can be minimized with proper stent selection and technique, and stent blocks can be managed with EUS-guided interventions in a majority of cases. Future comparative studies are required to establish the role of EUS-guided interventions in MHBO as rescue or primary therapy.

• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.452-461
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• 2005

In the star VPN (Virtual Private Network) topology, the traffic between the communicating two CPE(Customer Premise Equipment) VPN GW(Gateway)s nay be inefficiently transferred. Also, the Center VPN GW nav erperience the overload due to excessive packet processing overhead. As a solution to this problem, a direct tunnel can be established between the communicating two CPE VPN GWs using the IKE (Internet Key Exchange) mechanism of IPSec(IP Security). In this case, however, the tunnel establishment and management nay be complicated. In this paper, we propose a mechanism called' SVOT (Star VPN On-demand Tunnel)', which automatically establishes a direct tunnel between the communicating CPE VPN GWs based on demand. In the SVOT scheme, CPE VPN GWs determine whether it will establish a direct tunnel or not depending on the traffic information monitored. CPE VPN GW requests the information that is necessary to establishes a direct tunnel to the Center VPN GW Through a simulation, we investigate the performance of the scheme performs better than the SYST scheme with respect to scalability, traffic efficiency and overhead of Center VPN GW, while it shows similar performance to the FVST with respect to end-to-end delay and throughput.

• Journal of Korean Neurosurgical Society
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• v.30 no.5
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• pp.592-599
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• 2001

Objective : The anterior communicating artery(ACoA) is known to be the most frequent location of intracranial aneurysms, but the complex arterial anatomy of the ACoA region makes this aneurysm among the most difficult one to treat. In the treatment of ACoA aneurysms, the direction of aneurysmal fundus is known to be very important in the surgical tactics. All ACoA aneurysms in our series were classified according to its direction, and analyzed the clinical features in order to investigate the prognostic factors influencing upon the surgical outcome. Methods : The authors reviewed 236 cases of ruptured ACoA aneurysms that were operated from 1990 to 1997, were classified according to Pia's classification. Results : The incidence rate of the ACoA aneurysm was 35.1%(236/672). Ventral group was more common than dorsal group, especially in ventro-caudal projection subgroup(36.0%). Poor preoperative clinical grade(Hunt-Hess grade IV and V) patients were more common in dorsal group(13.1%) than ventral group(2.6%). Rebleeding and intracerebral hematoma were more commonly seen in ventral group. However, vasospasm, hydrocephalus, hyponatremia, and intraventricular hemorrhage were observed more frequently in dorsal group. Worse outcome was more common in dorsal group than ventral group, especially in dorso-caudal projection subgroup. Also, poor outcome was identified in patients with intracerebral hematoma, intraventricular hemorrhage, hyponatremia, and hypertension, although statistically insignificant. In cases with the A1 dominancy, there was no difference in surgical outcome between the right and left side approach. The higher the aneurysmal neck from the planum sphenoidale, the worse outcome via pterional approach. Conclusion : It seems that the preoperative clinical grade, aneurysmal direction, and the height of aneurysmal neck, especially in the pterional approach, would be the major prognostic factors, and that intracerebral hematoma, intraventricular hemorrhage, hyponatremia, hydrocephalus and the intraoperative aneurysmal rupture would be the minor prognostic factors.

• Journal of Korean Neurosurgical Society
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• v.58 no.3
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• pp.184-191
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• 2015

Objective : Anterior communicating artery (AcomA) aneurysms represent the most common intracranial aneurysms and challenging to treat due to complex vascularity. The purpose of this study was to report our experience of endovascular treatment of AcomA aneurysms. Methods : Between January 2003 and December 2013, we retrospectively reviewed the medical records of 134 AcomA aneurysm patients available more than 6 months conventional angiographic and clinical follow-up results. We focused on aneurismal or AcomA vascular characters, angiographic and clinical follow-up results, and retreatment. Results : The rate of ruptured cases was 75.4%, and the small (<10 mm) aneurysms were 96.3%. Based on the subtypes defined by dominance of A1, 79 patients (59%) had contralateral A1 hypoplasia or agenesis. The immediate post-procedural angiography confirmed complete occlusion in 75.4%, partial occlusion in 24.6%. Procedure related complications were observed in 25 (18.6%) patients. Most of the adverse events were asymptomatic. Follow-up conventional angiography at ${\geq}6$ months was performed in all patients (mean 16.3 months) and major recanalization was noted in 6.7% and regrowth in one case. The aneurysm size (p=0.016), and initial treatment results (p=0.00) were statistically significant risk factors related to aneurysm recurrence. An overall improvement in mRS was observed during the clinical follow-up period and no rebleeding episode occurred. Conclusion : This study demonstrated that endovascular treatment is an effective treatment modality for AcomA aneurysms with low morbidity. Patients should take long term clinical and angiographic follow-up in order to assess the recurrence and warrant retreatment, especially ruptured, large, and initially incomplete occluded aneurysms.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1188-1194
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• 2000

Objective : Internal carotid-posterior communicating artery(IC-PC) aneurysms can be clipped easily without any special preparations. Occasionally, however, it is difficult to clip the low-lying IC-PC aneurysms without some kinds of additional procedures. Clinical Material and Methods : We experienced four cases of low-lying IC-PC aneurysms, which the intradural anterior clinoidectomy and/or anterior petroclinoid fold(APF) resection was essential to expose the proximal side of the aneurysmal neck and/or proximal control. One patient harbored two low-lying IC-PC aneurysms bilaterally. The patients were divided into two groups according to the necessity of anterior clinoidectomy : Group I(n=4) that needed an intradural clinoidectomy and/or APF resection and Group II(n=29) that had IC-PC aneurysms, easily clipped without any special preparation. Also, various radiometric parameters were measured through the preoperative angiograms. Results : The incidence of such aneurysms was 12% among a total of thirty-three surgically treated IC-PC aneurysms during lasr 3 years. Among four cases, three cases presented with subarachnoid hemorrhage and all aneurysmal sac projected to postero-inferior direction. In our study, We initially considered the necessity of intraoperative anterior clinoid process(ACP) removal and/or resection of APF in cases of shorter distance less than 5.6mm between the proximal aneurysmal sac and tip of the ACP(p<0.001), and the proximal portion of aneurysmal neck has located below the interclinoid line(p=0.001). Conclusion : Through a careful preoperative evaluation, some radiometric parameters can be used to determine whether the ACP should be removed in clipping of the low-lying IC-PC aneurysms. Unlike to total removal of the ACP, the intradural partial anterior clinolidectomy and/or APF resection, which are more familiar to surgeons, reduce the risks of the premature rupture, operative time, and also contribute a more precise clip placement with proximal control than the extradural clinoidectomy.

• Journal of Korean Neurosurgical Society
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• v.38 no.2
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• pp.89-95
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• 2005

Objective : The purpose of this study is to analyze aneurysm morphology and define limitations and feasibility in endovascular Gugliemi detachable coil[GDC] embolization for anterior communicating artery [ACoA] aneurysms. Methods : From January 2000 through October 2003, 123patients were treated with endovascular coil embolization for ACoA aneurysms. There were 75women and 48men, with a mean age of 63years. All ruptured aneurysms were treated within 15days of rupture. Aneurysm morphology was classified according to neck size and projection of aneurysm dome as follows-A : neck of aneurysm <4mm & anterior projection, B : neck of aneurysm [4mm & anterior projection, C : neck of aneurysm<4mm & posterior [superior] projection, D : neck of aneurysm [4mm & posterior [superior] projection, E : neck of aneurysm<4mm & inferior projection, and F : neck of aneurysm [4mm & inferior projection. Endovascular procedures were categorized as either "successful" or "unsuccessful". Clinical follow-up was estimated at discharge and at 6months, post treatment results were classified according to Glasgow Outcome Scale[GOS]. Results : Successful embolization for ACoA was performed in 86patients of 123patients [69.9%]. Complete or near complete aneurysm occlusion was observed in 102patients [82.9%]; a neck remnant was observed in 6patients [4.9%]; partial embolization was done in 3patients [2.4%]; and embolization was attempted in 12patients [9.8%]. Among 55patients with follow-up angiographic results, 18patients [32.7%] were defined as recanalization of the aneurysm sac. Morphological analysis demonstrated that anterior projecting aneurysms and morphological classifications [morphological classifications worsens [A - D] chances of successful coil occlusion significantly decrease] were major factors in successful embolization, and, inferiorly projecting and wide neck [${\ge}4mm$] aneurysms are highly related to recanalization of aneurysms. Conclusion : Endovascular coil embolization of ACoA aneurysms shows good outcome in our study. Nevertheless, there is a limitation in the endovascular approach to ACoA, even though advanced modern techniques evolve rapidly. Compensatory surgical approach with the endovascular approach is required for successful treatment of ACoA aneurysms.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.2
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• pp.1-11
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• 2018

As a result of climate change, mountain sediment disasters due to localized heavy rain and mountain development are occuring more frequently, thus, increasing social attention to and demand for soil erosion control projects. However, since 2011 Seoul Wumyeon Mountain landslide, the public is expressing increasing anxiety as well as negative perception regarding defective project results. Therefore, this study investigated promotional terms and information media related to soil erosion control projects according to the consumer in order to increase awareness of soil erosion control projects. In this study, the information consumers were divided into experts and the general public and conducted a survey related to promotional terms and media for communicating relevant information. In the result, the experts chose landslide prevention and recovery projects (41.8%) as an appropriate promotional term for soil erosion control projects. The general public, however, chose mountain sediment disaster prevention projects (32.5%) as the appropriate promotional term. However, the analysis showed that it would be necessary to develop an promotional term that can encompass the concept of 'disaster prevention' including forest and soil disaster as the word 'landslide' can suggest soil erosion control is limited to landslides only. In the survey regarding the media for communicating information related to soil erosion control projects according to the consumer type, the experts preferred radio and TV as media to communicate the relevant information, while, among the general public, the youths preferred social media such as Facebook and Twitter (22.22%) and adults radio and TV (34.07%), As for the most effective way to promote soil erosion control projects, the experts chose traditional promotinal media such as newspaper, radio, and TV (0.172) whereas the adults and youths preferred the internet and Facebook (0.089). It appears that using the preferred media for communicating information related to soil erosion control projects according to the consumer type will be effective way to promote soil erosion control projects.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.436-448
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• 2000

Objectives : To identify the factors affecting users' satisfaction with the Order Communicating System(OCS) and to highlight the factors important for the successful establishment of OCS. Methods : A Users Satisfaction survey was sent to 4,513 people, consisting of 1,503 doctors, 2,379 nurses, 255 pharmacists and 370 administrative workers in 16 hospitals which had introduced OCS. The response rate was 63.9%. Measurement of users' satisfaction was peformed with the instrument which was used in Doll's study. Some aspects of Doll's instrument were adjusted according to the aims of this study. The classifying sections of this survey included age, job and status classification, computer experience, OCS education, duration of daily OCS use, type of order entering, number of personnel in the Hospital Information System's department, cost of OCS, problem frequency, proportion of work managed by hand, OCS type, and Hospital establishment type. Results : There was a positive correlation between satisfaction level and managerial status throughout all job classifications. Irrespective of the importance of OCS education as a factor relating to users' satisfaction, the additional work load caused by OCS lowered users' satisfaction. Different factors affected users' satisfaction according to job and status classification. The composition of factors affecting the pharmacist and administrative worker satisfaction levels was simpler than that of the doctor and nurse levels. There were no statistically significant differences between the actual computer experience duration of daily OCS use and users' satisfaction with OCS. Conclusions : There was an understandable relationship between users' attitude to OCS and factors affecting users' satisfaction. The results of this study could be used as a basis for the successful expansion of the operation of OCS. But more detailed studies on users' satisfaction and further improvements of methodologies are required for the successful establishment of OCS.

• Journal of Korean Neurosurgical Society
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• v.67 no.4
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• pp.411-417
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• 2024

Objective : To confirm the usefulness of the extradural anterior clinoidectomy during the clipping of a low riding posterior communicating artery (PCoA) aneurysm through cadaver dissection. Methods : Anatomic measurements of 12 adult cadaveric heads (24 sides total) were performed to compare the microsurgical exposure of the PCoA and internal carotid artery (ICA) before and after clinoidectomy. A standard pterional craniotomy and transsylvian approach were performed in all cadavers. The distance from the ICA bifurcation to the origin of PCoA (D1), pre-anterior clinoidectomy distance from the ICA bifurcation to tentorium (D2), post-anterior clinoidectomy distance from the ICA bifurcation to tentorium (D3), pre-anterior clinoidectomy distance from the tentorium to the origin of PCoA (D4) and post-anterior clinoidectomy distance from the tentorium to the origin of PCoA (D5) and the distance of the ICA obtained after anterior clinoidectomy (D6) were measured. We measured the precise thickness of the blade for the Yasargil clip with a digital precision ruler to confirm the usefulness of the extradural anterior clinoidectomy. Results : Twenty-four sites were dissected from 12 cadavers. The age of the cadavers was 79.83±6.25 years. The number of males was the same as the females. The space from the proximal origin of the PCoA to the preclinoid-tentorium (D4) was 1.45±1.08 mm (max, 4.01; min, 0.56). After the clinoidectomy, the space from the proximal origin of the PCoA to the postclinoid-tentorium (D5) was 3.612±1.15 mm (max, 6.14; min, 1.83). The length (D6) of the exposed proximal ICA after the extradural clinoididectomy was 2.17±1.04 mm on the lateral side and 2.16±0.89 mm on the medial side. The thickness of the Yasargil clip blade used during the clipping surgery was 1.35 mm measured with a digital precision ruler. Conclusion : The proximal length obtained by performing an external anterior clinoidectomy is about 2 mm, sufficient for proximal control during PCoA aneurysm surgery, considering the thickness of the aneurysm clips. In a subarachnoid hemorrhage, performing an extradural anterior clinoidectomy could prevent a devastating situation during PCoA aneurysm clipping.

• ETRI Journal
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• v.26 no.3
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• pp.203-217
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• 2004

This paper presents a method and architecture to analyze streaming media and multimedia conferencing traffic. Our method is based on detecting the transport protocol and port numbers that are dynamically assigned during the setup between communicating parties. We then apply such information to analyze traffic generated by the most popular streaming media and multimedia conferencing applications, namely, Windows Media, Real Networks, QuickTime, SIP and H.323. We also describe a prototype implementation of a traffic monitoring and analysis system that uses our method and architecture.