• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.75-83
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• 2009

PPC stands for the percentage of weekly assignments completed. It makes it possible to improve the performance of production planning and control systems. Recently, the cases of PPC application have been increasing because PPC is easy to apply to construction site. However, to evaluate the average of PPC or analyze PPC as time passes has some problem ; if PPC is the same, the average it is evaluated equally although there are variabilities in production system. Therefore, In order to evaluate the character of PPC in process of production this paper suggests the method of the evaluating PPC by using coefficient of variability besides PPC measurement.

• Membrane Journal
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• v.19 no.4
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• pp.341-347
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• 2009

Nanohybrid based on environmentally friendly and biodegradable polymer, poly propylene carbonate (PPC) and cloisite 20B (PPC/C-20B) have been synthesized by solution blending method and their morphology, thermal and water absorption properties have been evaluated. The structure of PPC/C-20B nanohybrid was confirmed by X-ray diffraction (XRD). The thermal property of PPC and PPC/C-20B nanohybrid were investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetric (DSC). The experimental results demonstrated that nanohybrid showed the highest thermal stability in TGA and DSC. TGA tests revealed that the thermal decomposition temperature ($T_{d50%}$) of the nanohybrid increased significantly, being $23^{\circ}C$ higher than that of pure PPC while DSC measurements indicated that the introduction of 5 mass% of clay increased the glass transition temperature from 21 to $30^{\circ}C$. Further the water absorption capacity of the PPC was significantly decreased by the incorporation of clay. Water absorption cause degradation of the coating by the moistures and affect the physical and mechanical performance. This result indicates that organic modifiers have effect on thermal and water absorption capacity of PPC and are of importance for the practical process and application of PPC.

• Journal of Nutrition and Health
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• v.32 no.8
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• pp.864-869
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• 1999

To investigate the effect of dietary phosphatidylcholine(PPC) supplement on memory improvement, biochemical study on the brain, and morphometric studies on the cholinergic neurons in the rat basal forebrain were undertaken. The pregnancy rats were divided into the normal control, the choline deficient and the PPC supplemental groups according to quantity of the PPC in diet. According to choline deficiency and PPC supplement after birth, the neonate rate of the normal control group were subdivided into the control diet(N-N) and the PPC supplied (N-S) groups, the choline deficient group were subdivided into the continually deficient (D-D), the control diet(D-N) and the PPC supplied groups(D-S), and the PPC supplemental group were subdivided into the control diet (S-N)and the continually supplied (S-S)group. The PPC supplemented diet was added 2% egg PPC in AIN 76 formula diet. PPC concentrations and cholinesterase(CE) activities were measured in the serum, the liver and the brain, respectively. Immunohistochemical stains for choline acetyltransferase(ChAT) was employed for the morphological and morphometric studies. The maze test was undertaken to evaluate memory improvement. PPC concentration and CE activities in the serum, liver and the brain were high in the PPC supplemental groups and low in the choline deficient groups. ChAT immunoreactivity neurons at the medial septal diagonal bond complex and the basal forebrain nucleus of Meynert were reduced in the choline deficient groups. Average failure rate for the maze test was the lowest in the S-S group and the highest in the D-D group. Insufficient choline suppley during the neuronal development would result in cholinergic neuronal damage, which could be prevented by adequate PPC supplement. It is consequently suggested that PPC supplement may be effective on memory improvement by maintaining the cholinergic neuronal activity in the basal forebrain of the rats.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.722-726
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• 2006

Last Planner System (LPS) developed by Lean Construction Institute consists of four steps: Master Schedule, Phase Schedule, Lookahead Planning and Weekly Work Plan. This paper focuses on the process of measuring Percent of Plan Completed (PPC) at the Weekly Work Plan stage. PPC means the percentage of weekly assignments completed. According to the results of the researches that deal with PPC from many other countries, we can assure the benefits of using PPC. However, the concept of PPC is unfamiliar in Korea construction industry. This paper analyzes the cases in which PPC is applied in other countries and compares them with the production control system in Korean construction industry. The results of this research will provide the time management system for using PPC in Korea.

• Journal of Hospice and Palliative Care
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• v.25 no.2
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• pp.85-97
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• 2022

Purpose: This study aimed to describe nurses' perceived needs and barriers to pediatric palliative care (PPC). Methods: Mixed methods with an embedded design were applied. An online survey was conducted for nurses who participated in the End-of-Life Nursing Education Consortium- Pediatric Palliative Care (ELNEC-PPC) train-the-trainer program, of whom 63 responded. Quantitative data were collected with a survey questionnaire developed through the Delphi method. The 47 items for needs and 15 items for barriers to PPC were analyzed with descriptive statistics. Qualitative data were collected through open-ended questions and analyzed with topic modeling techniques. Results: The mean scores of most subdomains of the PPC needs were 3.5 or higher out of 4, and those of PPC barriers ranged from 3.22 to 3.56, indicating the items in the questionnaire developed in this study properly reflect each factor. The needs for PPC were divided into 4 categories: "children and adolescents," "families," "PPC management system," and "community-based PPC." Meanwhile, PPC barriers were divided into 3 categories: "healthcare delivery system," "healthcare provider," and "client." The keywords derived from the topic modeling were perception, palliative, children, and education for necessities and lack, perception, medical care, professional care providers, service, and system for barriers to PPC. Conclusion: In this study, by using mixed-methods, items of nurses' perceived needs and barriers to PPC were identified, categorized, and weighted, and their meanings were explored. For the stable establishment of PPC, the priority should be given to improving perceptions of PPC, establishing an appropriate system, and training professional care providers.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.525-531
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• 2013

Purpose: To identify the apoptosis caused by Proparacaine hydrochloride (PPC), a topical anesthesia, applied to conjunctival cell lines and determine whether pigallocatechin-gallate (EGCG), has protective effects on. Methods: The conjunctival cell lines were treated with 0.5% of Alcaine$^{(R)}$, 0.5% of PPC and 0.01% of Benzalkonium chloride (BAC) for 15 minutes, respectively in order to investigate the effects of topical anesthesia on cells, and followed by cultured for 12 and 24 hours. The recovery effects were investigated by measuring level of cellular proliferation inhibiting using MTT assay and LDH assay. The conjunctival cell lines were pre-treated with EGCG $10{\mu}M$ for 3 hrs and post-treated with 0.5% PPC for 15 mins in order to investigate whether EGCG has protective effects, flow cytometry were performed in order to observe apoptosis. Results: A result of the additional culture of 12 and 24 hours and again immediately after the treatment for 15 minutes 0.5% of Alcaine$^{(R)}$, 0.5% of PPC, the 0.01% of BAC, cell viability was not increased in all groups (p<0.05). The cell viabilities were higher than in cells 3 hours post-treated with $10{\mu}M$ of EGCG and pre-treated PPC 0.5% (68.2%), compared to cells ($32.2{\pm}2.0%$) treated only with 0.5% of PPC. PPC 0.5% also induced apoptosis in the treated group was reduced by the addition of EGCG. Conclusions: It is considered that the EGCG has cell protective effects when it is added to PPC, a topical anesthesia, by improving cell viability and inhibiting apoptosis.

• Polymer(Korea)
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• v.37 no.2
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• pp.249-253
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• 2013

From poly(lactic acid) (PLA) and poly(propylene carbonate) (PPC) synthesized using $CO_2$, a PLA/PPC/PLA layered film is prepared by coextrusion and then stretched to uniaxial orientation. The mechanical, optical, and barrier properties and shrinkage of the prepared film were investigated in detail. The maximum shrinkage of PLA/PPC/PLA film reached to 60% at $75^{\circ}C$. With increasing PPC content, the ratio of shrinkage of the film was increased and its shrinkagerate was increased. The ratio of shrinkage of the film decreased with increasing stretching temperature. The prepared film has oxygen and vapor transmission barrier properties. In this study, the PLA/PPC/PLA film is expected to be commercialized as a environmentally friendly shrinkable film.

• The KIPS Transactions:PartB
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• v.10B no.1
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• pp.33-40
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• 2003

Data mining plays an important role in a knowledge discovery process and various algorithms of data mining can be selected for the specific purpose. Most of traditional hierachical clustering methode are suitable for processing small data sets, so they difficulties in handling large data sets because of limited resources and insufficient efficiency. In this study we propose a hybrid neural networks clustering technique, called PPC for Pre-Post Clustering that can be applied to large data sets and find unknown patterns. PPC combinds an artificial intelligence method, SOM and a statistical method, hierarchical clustering technique, and clusters data through two processes. In pre-clustering process, PPC digests large data sets using SOM. Then in post-clustering, PPC measures Similarity values according to cohesive distances which show inner features, and adjacent distances which show external distances between clusters. At last PPC clusters large data sets using the simularity values. Experiment with UCI repository data showed that PPC had better cohensive values than the other clustering techniques.

• Journal of Hospice and Palliative Care
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• v.17 no.4
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• pp.289-300
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• 2014

Purpose: The aim of this research was to explore nurses' knowledge of and attitudes toward pediatric palliative care (PPC) in Korea. Methods: A descriptive cross-sectional design was used. A total of 196 participants were recruited from the ELNEC-PPC course held in Seoul, Korea. All participants completed a 20-item survey questionnaire which assessed knowledge of and attitudes toward PPC using a 7-point Likert scale. Results: Nurses' knowledge of PPC correlated with their educational level and work experience in the pediatric unit and hospice care unit. The work experience in the pediatric unit, career length in PPC and completion of palliative education course made differences in the attitudes toward PPC. Married nurses scored significantly higher on the parental rights in determining palliative care service for their child, and nurses with master's degree or higher showed a higher level of understanding of and attitudes toward the differences between PPC and adult palliative care. Conclusion: The factors influencing nurses' knowledge of and attitudes toward PPC need be considered to develop a pediatric palliative training program.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.93-104
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• 2011

A conditional access system is an essential element in IPTV services enabling service providers to allow authorized access to their services only to paid subscribers. Currently, there are two types of IPTV service models, namely PPC (pay-per-channel) and PPV (pay-per-view). However, a more desirable model would be the flexible PPC model, in which subscribers are free to choose any combination of preferred channels and add/remove channels independently. In this paper, we first point out that a previously proposed key management scheme for F-PPC is not secure. We then propose a new conditional access system using 4-level key hierarchy to realize secure F-PPC services. Compared to existing schemes, the proposed system is very efficient, just requiring O(1) communication for key update.