Reduce Transmission Rates Research Articles

UTILIZATION OF HIGH-SPEED DSP ALGORITHMS OF CYCLIC REDUNDANCY CHECKING (CRC-15) ENCODER AND DECODER FOR CONTROLLER AREA NETWORK

Advanced driver assistance system (ADAS) performs an increasing improvement in active road safety and driving convenience. Controller Area Network (CAN) is now getting popular because of its expanding applications and widely utilizations in low-cost embedded systems from automation to medical industry. While implementing an effective and efficient mechanism for clock synchronization, serial operation causes the reduction of CAN transmission rate can have an adverse impact on the real-time applications of systems employing this protocol. Also, maintaining the reliability of this technology especially in safety services, a reliable system needs certain requirements like glitches management and troubleshooting in order to avoid certain occurrences of transmission error. In this paper we present a simulated Cyclic Redundancy Checking (CRC) encoder and decoder that perform high speed error detection for CAN using CRC-15. Digital Signal Processing (DSP) algorithms were used, namely pipelining, unfolding and retiming to attain the feasible iteration bound and critical path that is appropriate for CAN system. The source code for Encoder and Decoder has been formulated in Verilog Hardware Description Language (HDL) from actual simulation to implementation of this CRC-15 for CAN system.

Distributed non-fragile filtering in sensor networks with energy constraints

This paper investigates the distributed filtering problem for sensor networks with energy constraint and filter gain variation. Firstly, two strategies are proposed to reduce energy consumption, i.e., the measurement size and the transmission rate reduction strategies. To reduce the measurement size, a useful measurement selection policy is introduced to choose which element of local measurements is transmitted. The selected measurement, which has a smaller size than the original one is then stochastically transmitted. In order to reflect the imprecision in filter implementation, the additive filter gain variation problem is considered. Based on the switched system approach and some stochastic system analysis methods, a sufficient condition is obtained such that the filtering error system is exponentially stable in the mean-square sense, and a prescribed H∞ performance level is guaranteed. Filter gains are shown to be determined by solving a set of linear matrix inequalities (LMIs). Finally, a simulation example is given to demonstrate the effectiveness of the proposed design.

Effect of addition of nanoclay, beeswax, tween-80 and glycerol on physicochemical properties of guar gum films

Effect of addition of nanoclay (nanofil-116), beeswax, tween-80 and glycerol on physicochemical properties of guar gum (GG) films was studied using response surface methodology (RSM). Beeswax produced reduction in water vapor transmission rate (WVTR) and tensile strength (TS). An improvement in TS with reduction in WVTR was observed due to nanoclay. Concentrations of various additives were optimized to prepare films with improved properties. Optimized concentrations (beeswax: 0.63%; nanoclay: 2.5%; tween-80: 0.63%; glycerol: 11.87% w/w GG) resulted in TS of 98MPa and WVTR of 89g/m2/d. Compatibility between GG and beeswax was further increased using gamma irradiation. RSM study with 50kGy irradiated beeswax was performed and optimum concentration of tween-80 (0.88%), irradiated beeswax (50kGy) (1.21%), glycerol (13.91%), nanoclay (3.07%) w/w of GG resulted in films having TS of 122 MPa and WVTR of 69g/m2/d. Guar gum based films with improved mechanical and barrier properties were successfully prepared.

Conflicting Selection Pressures Will Constrain Viral Escape from Interfering Particles: Principles for Designing Resistance-Proof Antivirals.

The rapid evolution of RNA-encoded viruses such as HIV presents a major barrier to infectious disease control using conventional pharmaceuticals and vaccines. Previously, it was proposed that defective interfering particles could be developed to indefinitely control the HIV/AIDS pandemic; in individual patients, these engineered molecular parasites were further predicted to be refractory to HIV’s mutational escape (i.e., be ‘resistance-proof’). However, an outstanding question has been whether these engineered interfering particles—termed Therapeutic Interfering Particles (TIPs)—would remain resistance-proof at the population-scale, where TIP-resistant HIV mutants may transmit more efficiently by reaching higher viral loads in the TIP-treated subpopulation. Here, we develop a multi-scale model to test whether TIPs will maintain indefinite control of HIV at the population-scale, as HIV (‘unilaterally’) evolves toward TIP resistance by limiting the production of viral proteins available for TIPs to parasitize. Model results capture the existence of two intrinsic evolutionary tradeoffs that collectively prevent the spread of TIP-resistant HIV mutants in a population. First, despite their increased transmission rates in TIP-treated sub-populations, unilateral TIP-resistant mutants are shown to have reduced transmission rates in TIP-untreated sub-populations. Second, these TIP-resistant mutants are shown to have reduced growth rates (i.e., replicative fitness) in both TIP-treated and TIP-untreated individuals. As a result of these tradeoffs, the model finds that TIP-susceptible HIV strains continually outcompete TIP-resistant HIV mutants at both patient and population scales when TIPs are engineered to express >3-fold more genomic RNA than HIV expresses. Thus, the results provide design constraints for engineering population-scale therapies that may be refractory to the acquisition of antiviral resistance.

Location of Iron and Ferritin in the Midgut of the yellow fever mosquito, Aedes aegypti

Dengue and Yellow Fever are caused by viruses transmitted by mosquitoes that each year infect 390 million and 200,000 people, respectively, and cause more than 2 million deaths. For mosquito eggs to develop and produce viable offspring, iron is required as an essential nutrient from the blood meal. Our previous research has shown iron from the blood meal is absorbed and transported by ferritin from the midgut to the ovaries in Aedes aegypti (yellow fever mosquito). Thus, understanding iron accumulation and utilization in the mosquito midgut is important to finding potential strategies to interfere with mosquito fecundity, decrease mosquito populations, and reduce transmission rates of vector‐borne diseases. However, it is unknown where in the midgut iron accumulates after a blood meal. To demonstrate this, Ae. aegypti midguts were dissected from sugar fed, 24 h post‐blood meal (PBM), and 72 h PBM animals to measure tissue iron accumulation after a blood meal by iron inductively coupled plasma mass spectrometry (ICP‐MS). Dissected midguts were also stained with Prussian Blue to visualize ferric iron deposition. Our results indicate that iron is present in the midgut prior to a blood meal, accumulates at 24 h PBM, and decreases by 72 h PBM, and the deposition of ferric iron is observed throughout the tissue before and after a blood meal. Further, immunohistochemistry studies of the midguts show three different subunits of the iron storage and transport protein, ferritin. Coalescence of ferritin and iron in mosquito midguts confirms the role of ferritin in this tissue for export of iron to other tissues, including the ovaries for oogenesis and ovarian homeostasis.Support or Funding InformationThis research was supported by funds from the Arizona Agricultural Experiment Station, the College of Agriculture and Life Sciences, the Undergraduate Biology Research Program, and the Honors College at the University of Arizona.

Energy-Efficient Distributed Filtering in Sensor Networks: A Unified Switched System Approach.

This paper is concerned with the energy-efficient distributed filtering in sensor networks, and a unified switched system approach is proposed to achieve this goal. For the system under study, the measurement is first sampled under nonuniform sampling periods, then the local measurement elements are selected and quantized for transmission. Then, the transmission rate is further reduced to save constrained power in sensors. Based on the switched system approach, a unified model is presented to capture the nonuniform sampling, the measurement size reduction, the transmission rate reduction, the signal quantization, and the measurement missing phenomena. Sufficient conditions are obtained such that the filtering error system is exponentially stable in the mean-square sense with a prescribed H∞ performance level. Both simulation and experiment studies are given to show the effectiveness of the proposed new design technique.

Mathematical Modeling of the Spread of an Epidemic Disease-Mumps

Over one-quarter of the Cauvery delta region people are at risk from epidemic diseases and the majority is mumps infections. Molecular evidence suggests spread has been almost exclusively through human-to-human contact. Social factors are clearly important to understand the epidemic and ways in which it might be spreads are analyzed. The present paper focuses on People in the villages of kamalapuram, Punavasal and sithamalli in Tiruvarur district mauled by the mumps outbreak-an outbreak is declared if at least five cases of a disease are found from a place-believe that Goddess Durga has entered the child's body and will only leave if pleased with worship. Children suffering from mumps often develop secondary, potentially lethal infections like measles, pneumonia, diarrhoea and encephalitis. Mumps is vaccine preventable, but a vaccination card-a checklist of vaccines that should be given to a child at different stages of growth-is an unheard-which shows the lack of awareness and seriousness about their children's health. In this paper we offer some data and observations relating to the Mumps epidemic, We propose that greater attention should be paid to rural areas for the disease. A concluding discussion considers what assistance might be necessary if rural communities are to reduce transmission rates.

Energy‐efficient distributed control of large‐scale systems: A switched system approach

SummaryThis paper is concerned with the sensor‐network‐based distributed control of large‐scale systems with the power constraint. In the underlying system, the measurement is firstly sampled under nonuniform sampling periods, which are varying in a given set. Then, the measurement size reduction technique and communication rate reduction method are used to save the constrained power in sensor networks. Specifically, only one element of sampled measurement is chosen at each sampling time instant, and it is then quantized and transmitted to the neighbouring controllers. Based on the switched system approach, a unified model is presented to capture the nonuniform sampling, the measurement size reduction, the transmission rate reduction and the controller failure phenomenon. A new sufficient condition is obtained such that the filtering error system is exponentially stable in the mean‐square sense with a prescribed H∞ performance level. Based on this condition, the controller gains are designed by using the cone complementarity linearization algorithm. Finally, a simulation study is given to show the effectiveness of the proposed new design technique. Copyright © 2015 John Wiley & Sons, Ltd.

Reduction of HIV transmission rates from mother to child in the era of antiretroviral therapy in the Lake Victoria zone, Tanzania

Background: Since the introduction of prevention of mother to child transmission (PMTCT) in Tanzania, HIV infection rates have been reduced in different regions across the country. However, there is limited published data from the Lake Victoria zone of Tanzania regarding the effectiveness of various regimens used for PMTCT. This study was done to assess the effectiveness of antiretroviral therapy in preventing mother to child transmission of HIVMethods: Infants aged ≤18 months born to HIV positive mothers undertaking PMTCT programme and those with no intervention program from Mara, Kagera, Mwanza and Shinyanga were tested for HIV-1 DNA polymerase chain reaction (PCR). Data were analysed using STATA version 10.0 to assess factors associated with outcome.Results: A total of 1,005 study subjects were enrolled in the study. Of these 55% (554/1005) were females. Majority (82.6%; 830/1005) of the infants studied were aged 1-6 months. The median age of the infant studied was 3 months (IQR 2-4). Out of 1005 non-repetitive samples; 61(6.1%) were HIV-1 DNA PCR positive. Positive dried blood spots (DBS) rates by region were 6.4%, 5.9%, 5.6% and 5.1% in Mwanza, Mara, Kagera and Shinyanga, respectively. During pregnancy interventions, the positive rate for women with no therapy was 12.6% and for zidovudine alone was 5.4% while for triple antiretroviral therapy was 0.5%. Women who were in highly active antiretroviral therapy (HAART) during pregnancy had significantly lower positive rate than those without HAART treatment (p=0.001). Of 755 infants who received nevirapine, 3.9% were DBS positive compared to 12.8% of those who didn’t receive nevirapine (p=0.001).Conclusion: The use of antiretroviral therapy in the PMTCT programme is effective in reducing HIV transmission from mother to child.

Distributed Joint Source-Channel Coding With Copula-Function-Based Correlation Modeling for Wireless Sensors Measuring Temperature

Wireless sensor networks (WSNs) deployed for temperature monitoring in indoor environments call for systems that perform efficient compression and reliable transmission of the measurements. This is known to be a challenging problem in such deployments, as highly efficient compression mechanisms impose a high computational cost at the encoder. In this paper, we propose a new distributed joint source-channel coding (DJSCC) solution for this problem. Our design allows for efficient compression and error-resilient transmission, with low computational complexity at the sensor. A new Slepian–Wolf code construction, based on non-systematic Raptor codes, is devised that achieves good performance at short code lengths, which are appropriate for temperature monitoring applications. A key contribution of this paper is a novel Copula-function-based modeling approach that accurately expresses the correlation amongst the temperature readings from colocated sensors. Experimental results using a WSN deployment reveal that, for lossless compression, the proposed Copula-function-based model leads to a notable encoding rate reduction (of up to 17.56%) compared with the state-of-the-art model in the literature. Using the proposed model, our DJSCC system achieves significant rate savings (up to 41.81%) against a baseline system that performs arithmetic entropy encoding of the measurements. Moreover, under channel losses, the transmission rate reduction against the state-of-the-art model reaches 19.64%, which leads to energy savings between 18.68% to 24.36% with respect to the baseline system.

HIV testing of construction workers in the Western Cape, South Africa

With an infection rate estimated at 14%, the South African construction industry is one of the economic sectors most adversely affected by the HIV/AIDS pandemic. Construction workers are considered a high-risk group. The provision and uptake of voluntary counselling and testing (VCT) is critical to reducing transmission rates. This study examined the testing behaviour of site-based construction workers in terms of demographic and lifestyle risk behaviour characteristics to help inform better strategies for work-based interventions by construction firms. A total of 512 workers drawn from six firms operating on 18 construction sites in the Western Cape province participated in the study. Twenty-seven per cent of the participants reported never having been tested for HIV. Results indicate that females (aOR = 4.45, 95% CI, 1.25–15.82), older workers (aOR = 1.40, 95% CI, 1.08–1.81), permanent workers (aOR = 1.67, 95% CI, 1.11–2.50) and workers whom had previously used a condom (aOR = 1.93, 95% CI, 1.02–3.65) were significantly more likely to have been tested. Ethnicity was not significantly related to prior testing. Identification of these subgroups within the industry has implications for the development of targeted work-based intervention programmes to promote greater HIV testing among construction workers in South Africa.

A systematic review and meta-analysis of HIV prevention interventions for socioeconomically disadvantaged ethnic minority women in OECD member countries

Background: Recently there have been many encouraging developments in the global effort to combat HIV and AIDS. The latest data collected by UNAIDS on the status of the disease showed a 33% reduction in new HIV cases since 2001 and a decrease of 700,000 deaths annually since the peak in 2005. 1 Within the 34 countries that make up the Organization for Economic Cooperation and Development (OECD), public health efforts have been successful in reducing the incidence of AIDS and improving the survival of those infected with HIV. 2 However, the incidence of new HIV infections remain stubbornly high with socioeconomically deprived communities, and women in particular, making up a disproportionate number of new cases. 3 There is a need for a greater understanding of the prevention interventions which can successfully educate this population, change behaviors associated with transmission and ultimately reduce the spread of sexually transmitted diseases such as HIV. The aim of this work was to identify, characterize and evaluate health interventions aimed at preventing HIV infection in women from socioeconomically disadvantaged ethnic mintority groups in OECD countries. Methods: A systematic review was undertaken of available publications related to HIV prevention interventions for socioeconomically deprived ethnic minority women in OECD member countries. Specific search strategies were designed for the databases Medline (Ovid), CINAHL, Embase, Scopus, and Web of Knowledge. Other searches were also done using relevant keywords in different databases such as Cochrane Library, CRD Databases, metaRegister of Controlled Trials, EURONHEED, CEA Registry, and European Action Program for Health Inequities, among others. When possible, a meta-analysis was performed using standardized mean differences to obtain aggregate estimates of effect size with 95% confidence intervals. Two reviewers independently extracted all the information and critically appraised the studies. Findings: We identified 34 articles analyzing 43 different prevention interventions with a total number of 13,318 participants. All of the interventions were carried out in the United States. The majority of the interventions were based on cognitivebehavioral models directed principally at reducing risky behaviors and were culturally adapted to the target population. Most programs obtained some benefits over control groups in the outcome measures of HIV knowledge, risk related behaviors and STD transmission reduction. A meta-analysis of 5 randomized controlled trials showed a 41% reduction in STD transmission rates (RR .59: 95% CI .46-.75; p < 0.05). Interpretation: HIV prevention interventions for socioeconomically deprived ethnic minority women are efficacious at improving knowledge of HIV, reducing risky behaviors associated with transmission as well as reducing the transmission of STD’s. Future prevention programming should incorporate the identified characteristics associated with successful behavior modification and disease prevention. Additional research is needed of this population outside of the United States. Funding: None. Abstract #: 02CD017

Proximate context of HIV-related stigma and utilization of skilled childbirth services in Uganda

Background: Recently there have been many encouraging developments in the global effort to combat HIV and AIDS. The latest data collected by UNAIDS on the status of the disease showed a 33% reduction in new HIV cases since 2001 and a decrease of 700,000 deaths annually since the peak in 2005. 1 Within the 34 countries that make up the Organization for Economic Cooperation and Development (OECD), public health efforts have been successful in reducing the incidence of AIDS and improving the survival of those infected with HIV. 2 However, the incidence of new HIV infections remain stubbornly high with socioeconomically deprived communities, and women in particular, making up a disproportionate number of new cases. 3 There is a need for a greater understanding of the prevention interventions which can successfully educate this population, change behaviors associated with transmission and ultimately reduce the spread of sexually transmitted diseases such as HIV. The aim of this work was to identify, characterize and evaluate health interventions aimed at preventing HIV infection in women from socioeconomically disadvantaged ethnic mintority groups in OECD countries. Methods: A systematic review was undertaken of available publications related to HIV prevention interventions for socioeconomically deprived ethnic minority women in OECD member countries. Specific search strategies were designed for the databases Medline (Ovid), CINAHL, Embase, Scopus, and Web of Knowledge. Other searches were also done using relevant keywords in different databases such as Cochrane Library, CRD Databases, metaRegister of Controlled Trials, EURONHEED, CEA Registry, and European Action Program for Health Inequities, among others. When possible, a meta-analysis was performed using standardized mean differences to obtain aggregate estimates of effect size with 95% confidence intervals. Two reviewers independently extracted all the information and critically appraised the studies. Findings: We identified 34 articles analyzing 43 different prevention interventions with a total number of 13,318 participants. All of the interventions were carried out in the United States. The majority of the interventions were based on cognitivebehavioral models directed principally at reducing risky behaviors and were culturally adapted to the target population. Most programs obtained some benefits over control groups in the outcome measures of HIV knowledge, risk related behaviors and STD transmission reduction. A meta-analysis of 5 randomized controlled trials showed a 41% reduction in STD transmission rates (RR .59: 95% CI .46-.75; p < 0.05). Interpretation: HIV prevention interventions for socioeconomically deprived ethnic minority women are efficacious at improving knowledge of HIV, reducing risky behaviors associated with transmission as well as reducing the transmission of STD’s. Future prevention programming should incorporate the identified characteristics associated with successful behavior modification and disease prevention. Additional research is needed of this population outside of the United States. Funding: None. Abstract #: 02CD017

EFFECT OF ORGANICALLY MODIFIED MONTMORILLONITE CLAY ON MORPHOLOGICAL, PHYSICOMECHANICAL, THERMAL STABILITY, AND WATER VAPOR TRANSMISSION RATE PROPERTIES OF BIIR-CO RUBBER NANOCOMPOSITE

ABSTRACT Rubber nanocomposites based on bromobutyl rubber (BIIR), polyepichlorohydrin rubber (CO), carbon black (CB), and organically modified montmorillonite clay (NC) were prepared via melt compounding technique. Effects of NC dosage on various properties of the developed BIIR-CO nanocomposites were studied. Morphological characteristics of the BIIR-CO nanocomposite revealed a good level of clay dispersion. Scanning electron microscopy analyses of the tensile fractured surfaces of the nanocomposites revealed the existence of a good interaction between NC-CB. Hybrid microstructure development between NC and CB, clay exfoliation, and improved filler dispersion in the quaternary nanocomposite significantly contributed to the overall enhancement of properties. The addition of nanoclay increases the modulus up to 54%, tear strength up to 20%, and other physicomechanical properties of the rubber nanocomposite. However, higher nanoclay dose results in the agglomeration of clay particles predominantly. An increase in the volume fraction of nanoclay platelets depreciates the thermal degradation of the BIIR-CO nanocomposites. The tortuous path offered by NC is pivotal in the significant reduction in the water vapor transmission rate (up to 30% reduction). Contact angle measurements reveal the importance of nanoclay dispersion in subsiding the surface hydrophilic nature of the nanocomposite.

Mechanical and barrier properties of guar gum based nano-composite films

Guar gum based nano-composite films were prepared using organically modified (cloisite 20A) and unmodified (nanofil 116) nanoclays. Effect of nanoclay incorporation on mechanical strength, water vapor barrier property, chromatic characteristics and opacity of films was evaluated. Nano-composites were characterized using X-ray scattering, FTIR and scanning electron microscopy. A nanoclay concentration dependent increase in mechanical strength and reduction in water vapor transmission rate was observed. Films containing nanofil 116 (2.5% w/w guar gum) and closite 20A (10% w/w guar gum) demonstrated a 102% and 41% higher tensile strength, respectively, as compared to the control. Lower tensile strength of cloisite 20A films as compared to nanofil 116 films was due to its incompatibility with guar gum. X-ray scattering analysis revealed that interstitial spacing between nanofil 116 and cloisite 20A sheets increased due to intercalation by guar gum polymer. This resulted in improved mechanical and barrier properties of nano-composites compared to control.

Fundamental Limits of Caching With Secure Delivery

Caching is emerging as a vital tool for alleviating the severe capacity crunch in modern content-centric wireless networks. The main idea behind caching is to store parts of popular content in end-users' memory and leverage the locally stored content to reduce peak data rates. By jointly designing content placement and delivery mechanisms, recent works have shown order-wise reduction in transmission rates in contrast to traditional methods. In this work, we consider the secure caching problem with the additional goal of minimizing information leakage to an external wiretapper. The fundamental cache memory vs. transmission rate trade-off for the secure caching problem is characterized. Rather surprisingly, these results show that security can be introduced at a negligible cost, particularly for large number of files and users. It is also shown that the rate achieved by the proposed caching scheme with secure delivery is within a constant multiplicative factor from the information-theoretic optimal rate for almost all parameter values of practical interest.

Performance of Cooperative Diversity with Constellation Rearrangement in Multi-hop Wireless Networks

The purpose of this paper is to evaluate the performance of cooperative diversity in distributed grouped two-hop and multi-hop relaying networks consisting of single-antenna terminals with constellation rearrangement. Simulation results, for phase shift keyed and quadrature amplitude modulation signals in the single carrier Rayleigh channel, show that the use of the cooperative diversity with a constellation rearrangement scheme improve the error probability performance in a power constrained, grouped multi-hop relaying network operating in a multi-path fading environment. The performance of the system will be improved without reduction of Transmission rate by using constellation rearrangement. Finally, the proposed scheme is evaluated through NS2 simulation from the view of throughput in order to investigate the interaction between physical layer and MAC layer.

Super Stretchy Polymer Multilayer Thin Film with High Gas Barrier.

Unlike ionically bonded or clay-loaded gas barrier thin films, which easily crack when moderately stretched, hydrogen-bonded poly(acrylic acid) (PAA)/poly(ethylene oxide) (PEO) multilayer thin films remain crack-free. Even after 100% strain, these nanocoatings provide more than a 5× reduction in oxygen transmission rate. This study shows that the lowest modulus PAA/PEO thin film is obtained at pH 3, but maintains a high barrier. A total of 20 PAA/PEO bilayers (367 nm thick) on 1.58 mm rubber reduced the oxygen transmission rate by 1 order of magnitude. Stretching from 25-100% caused plastic deformation and reduced gas barrier, but the oxygen transmission rate remained at least 5× lower than the uncoated rubber. The ability to prevent cracking and preserve the gas barrier up to 100% strain provides a tremendous opportunity for reducing weight and improving the barrier of elastomeric materials.

Epidemiological Modeling of Bovine Brucellosis in India.

The study objective is to develop an epidemiological model of brucellosis transmission dynamics among cattle in India and to estimate the impact of different prevention and control strategies. The prevention and control strategies are test-and-slaughter, transmission rate reduction, and mass vaccination. We developed a mathematical model based on the susceptible-infectious-recovered epidemic model to simulate brucellosis transmission dynamics, calibrated to the endemically stable levels of bovine brucellosis prevalence of cattle in India. We analyzed the epidemiological benefit of different rates of reduced transmission and vaccination. Test-and-slaughter is an effective strategy for elimination and eradication of brucellosis, but socio-cultural constraints forbid culling of cattle in India. Reducing transmission rates lowered the endemically stable levels of brucellosis prevalence correspondingly. One-time vaccination lowered prevalence initially but increased with influx of new susceptible births. While this epidemiological model is a basic representation of brucellosis transmission dynamics in India and constrained by limitations in surveillance data, this study illustrates the comparative epidemiological impact of different bovine brucellosis prevention and control strategies.

2-SD 방식에 기반한 브로드캐스트 암호시스템의 안전성 분석

Broadcast encryption is a cryptographic primitive that allows a sender to securely transmit a message to a set of receivers. The most influential broadcast encryption system was proposed in 2001 by Naor, Naor, Lotspiech, based on binary trees and the Subset Difference (SD) method. In 2006, Jang, Nyang, and Song suggested a new broadcast encryption system that can reduce transmission rate by 50% compared to the SD method, by introducing the so-called '2-SD' method. Their result was later given the registration of a patent in Korea (registration number: 100879083). Unfortunately, however, this paper shows that Jang et. al.'s broadcast encryption system is not secure against collusion attacks that are considered as being the basic security requirement in designing broadcast encryption.